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- <head>
- <title>Getting Started with LLVM System</title>
- </head>
-
- <body bgcolor=white>
- <center><h1>Getting Started with the LLVM System<br><font size=3>By: <a
- href="mailto:gshi1@uiuc.edu">Guochun Shi</a>,
- <a href="mailto:sabre@nondot.org">Chris Lattner</a>,
- <a href="mailto:criswell@uiuc.edu">John Criswell</a>,
- <a href="http://misha.brukman.net">Misha Brukman</a>, and
- <a href="http://www.cs.uiuc.edu/~vadve">Vikram Adve</a>
- </font></h1></center>
-
- <!--=====================================================================-->
- <h2><a name="Contents">Contents</a></h2>
- <!--=====================================================================-->
+<head>
+ <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+ <title>Getting Started with LLVM System</title>
+ <link rel="stylesheet" href="llvm.css" type="text/css">
+</head>
+<body>
+
+<div class="doc_title">
+ Getting Started with the LLVM System
+</div>
+
+<ul>
+ <li><a href="#overview">Overview</a>
+ <li><a href="#quickstart">Getting Started Quickly (A Summary)</a>
+ <li><a href="#requirements">Requirements</a>
+ <ol>
+ <li><a href="#hardware">Hardware</a></li>
+ <li><a href="#software">Software</a></li>
+ <li><a href="#brokengcc">Broken versions of GCC and other tools</a></li>
+ </ol></li>
- <ul>
- <li><a href="#overview">Overview</a>
+ <li><a href="#starting">Getting Started with LLVM</a>
+ <ol>
+ <li><a href="#terminology">Terminology and Notation</a></li>
+ <li><a href="#environment">Setting Up Your Environment</a></li>
+ <li><a href="#unpack">Unpacking the LLVM Archives</a></li>
+ <li><a href="#checkout">Checkout LLVM from Subversion</a></li>
+ <li><a href="#git_mirror">LLVM GIT mirror</a></li>
+ <li><a href="#installcf">Install the GCC Front End</a></li>
+ <li><a href="#config">Local LLVM Configuration</a></li>
+ <li><a href="#compile">Compiling the LLVM Suite Source Code</a></li>
+ <li><a href="#cross-compile">Cross-Compiling LLVM</a></li>
+ <li><a href="#objfiles">The Location of LLVM Object Files</a></li>
+ <li><a href="#optionalconfig">Optional Configuration Items</a></li>
+ </ol></li>
+
+ <li><a href="#layout">Program layout</a>
+ <ol>
+ <li><a href="#examples"><tt>llvm/examples</tt></a></li>
+ <li><a href="#include"><tt>llvm/include</tt></a></li>
+ <li><a href="#lib"><tt>llvm/lib</tt></a></li>
+ <li><a href="#projects"><tt>llvm/projects</tt></a></li>
+ <li><a href="#runtime"><tt>llvm/runtime</tt></a></li>
+ <li><a href="#test"><tt>llvm/test</tt></a></li>
+ <li><a href="#test-suite"><tt>test-suite</tt></a></li>
+ <li><a href="#tools"><tt>llvm/tools</tt></a></li>
+ <li><a href="#utils"><tt>llvm/utils</tt></a></li>
+ </ol></li>
+
+ <li><a href="#tutorial">An Example Using the LLVM Tool Chain</a>
<ol>
- <li><a href="#requirements">Requirements</a>
- <ol>
- <li><a href="#hardware">Hardware</a>
- <li><a href="#software">Software</a>
- </ol>
+ <li><a href="#tutorial4">Example with llvm-gcc4</a></li>
</ol>
- <li><a href="#starting">Getting started with LLVM</a>
- <ol>
- <li><a href="#quickstart">Getting Started Quickly (A Summary)</a>
- <li><a href="#terminology">Terminology and Notation</tt></a>
- <li><a href="#environment">Setting Up Your Environment</a>
- <li><a href="#unpack">Unpacking the LLVM Archives</a>
- <li><a href="#checkout">Checkout LLVM from CVS</a>
- <li><a href="#installcf">Install the C Front End</a>
- <li><a href="#config">Local LLVM Configuration</tt></a>
- <li><a href="#compile">Compiling the LLVM Suite Source Code</a>
- <li><a href="#objfiles">The Location of LLVM Object Files</tt></a>
- </ol>
- <li><a href="#layout">Program layout</a>
- <ol>
- <li><a href="#cvsdir"><tt>CVS</tt> directories</a>
- <li><a href="#include"><tt>llvm/include</tt></a>
- <li><a href="#lib"><tt>llvm/lib</tt></a>
- <li><a href="#test"><tt>llvm/test</tt></a>
- <li><a href="#tools"><tt>llvm/tools</tt></a>
- <li><a href="#utils"><tt>llvm/utils</tt></a>
- </ol>
- <li><a href="#cfront">Compiling the LLVM C Front End</a>
- <li><a href="#tutorial">An Example Using the LLVM Tool Chain</a>
- <li><a href="#problems">Common Problems</a>
- <li><a href="#links">Links</a>
- </ul>
-
-
- <!--=====================================================================-->
- <center>
- <h2><a name="overview"><b>Overview</b></a></h2>
- </center>
- <!--=====================================================================-->
-
- Welcome to LLVM! In order to get started, you first need to know some
- basic information.
-
- <p>
- First, LLVM comes in two pieces. The first piece is the LLVM suite. This
- contains all of the tools, libraries, and header files needed to use the
- low level virtual machine. It also contains a test suite that can be used
- to test the LLVM tools and the C front end.
- <p>
- The second piece is the C front end. This component provides a version
- of GCC that compiles C code into LLVM bytecode. Currently, the C front end
- is a modified version of GCC 3.4 (we track the GCC 3.4 development).
- Once compiled into LLVM bytecode, a program can be manipulated with the
- LLVM tools from the LLVM suite.
-
- <!--=====================================================================-->
- <h3><a name="requirements"><b>Requirements</b></a></h3>
- <!--=====================================================================-->
-
- Before you begin to use the LLVM system, review the requirements given
- below. This may save you some trouble by knowing ahead of time what
- hardware and software you will need.
-
- <!--=====================================================================-->
- <h4><a name="hardware"><b>Hardware</b></a></h4>
- <!--=====================================================================-->
- LLVM is known to work on the following platforms:
- <ul>
- <li> Linux on x86
- <ul>
- <li> Approximately 760 MB of Free Disk Space
- <ul>
- <li>Source code: 30 MB
- <li>Object code: 670 MB
- <li>C front end: 60 MB
- </ul>
- </ul>
-
- <p>
-
- <li> Solaris on SparcV9 (Ultrasparc)
- <ul>
- <li> Approximately 1.24 GB of Free Disk Space
- <ul>
- <li>Source code: 30 MB
- <li>Object code: 1000 MB
- <li>C front end: 210 MB
- </ul>
- </ul>
- </ul>
-
- <p>
- If you want to compile your own version of the C front end, you will need
- additional disk space:
- </p>
-
- <ul>
- <li>Linux on x86
- <ul>
- <li> Approximately 249 MB of Free Disk Space
- <ul>
- <li>Source code: 146 MB
- <li>Object code: 82 MB
- <li>Installed binaries: 21 MB
- </ul>
- </ul>
-
- <p>
-
- <li>Solaris on Sparc
- <ul>
- <li> Approximately 264 MB of Free Disk Space
- <ul>
- <li>Source code: 146 MB
- <li>Object code: 93 MB
- <li>Installed binaries: 25 MB
- </ul>
- </ul>
- </ul>
-
- <p>
- LLVM <i>may</i> compile on other platforms. The LLVM utilities should work
- on other platforms, so it should be possible to generate and produce LLVM
- bytecode on unsupported platforms (although bytecode generated on one
- platform may not work on another platform). However, the code generators
- and Just-In-Time (JIT) compilers only generate SparcV9 or x86 machine code.
- </p>
-
- <!--=====================================================================-->
- <h4><a name="software"><b>Software</b></a></h4>
- <!--=====================================================================-->
- <p>
-
- Unpacking the distribution requires the following tools:
- <dl compact>
- <dt>GNU Zip (gzip)
- <dt>GNU Tar
- <dd>
- These tools are needed to uncompress and unarchive the software.
- Regular Solaris <tt>tar</tt> may work for unpacking the TAR archive but
- is untested.
- </dl>
-
- Compiling LLVM requires that you have several different software packages
- installed:
-
- <dl compact>
- <dt> GCC
- <dd>
- The GNU Compiler Collection must be installed with C and C++ language
- support. GCC 3.2.x works, and GCC 3.x is generally supported.
-
- <p>
- Note that we currently do not support any other C++ compiler.
- </p>
-
- <dt> GNU Make
- <dd>
- The LLVM build system relies upon GNU Make extensions. Therefore, you
- will need GNU Make (sometimes known as gmake) to build LLVM.
- <p>
-
- <dt> Flex and Bison
- <dd>
- The LLVM source code is built using flex and bison. You will not be
- able to configure and compile LLVM without them.
- <p>
-
- <dt> GNU M4
- <dd>
- If you are installing Bison on your machine for the first time, you
- will need GNU M4 (version 1.4 or higher).
- </dl>
+ <li><a href="#problems">Common Problems</a>
+ <li><a href="#links">Links</a>
+</ul>
- <p>
- There are some additional tools that you may want to have when working with
- LLVM:
- </p>
-
- <ul>
- <li>GNU Autoconf
- <li>GNU M4
- <p>
- If you want to make changes to the configure scripts, you will need
- GNU autoconf (2.53 or higher), and consequently, GNU M4 (version 1.4
- or higher).
- </p>
- </ul>
-
-
- <p>The <a href="starting">next section</a> of this guide is meant to get
- you up and running with LLVM and to give you some basic information about
- the LLVM environment. The <a href"#quickstart">first subsection</a> gives
- a short summary for those who are already familiar with the system and
- want to get started as quickly as possible.
-
- <p>The later sections of this guide describe the <a
- href="#layout">general layout</a> of the the LLVM source-tree, a <a
- href="#tutorial">simple example</a> using the LLVM tool chain, and <a
- href="#links">links</a> to find more information about LLVM or to get
- help via e-mail.
-
- <!--=====================================================================-->
- <center>
- <h2><a name="starting"><b>Getting Started with LLVM</b></a></h2>
- </center>
- <!--=====================================================================-->
-
- <!--=====================================================================-->
- <h3><a name="quickstart"><b>Getting Started Quickly (A Summary)</b></a></h3>
- <!--=====================================================================-->
-
- Here's the short story for getting up and running quickly with LLVM:
+<div class="doc_author">
+ <p>Written by:
+ <a href="mailto:criswell@uiuc.edu">John Criswell</a>,
+ <a href="mailto:sabre@nondot.org">Chris Lattner</a>,
+ <a href="http://misha.brukman.net">Misha Brukman</a>,
+ <a href="http://www.cs.uiuc.edu/~vadve">Vikram Adve</a>, and
+ <a href="mailto:gshi1@uiuc.edu">Guochun Shi</a>.
+ </p>
+</div>
+
+
+<!-- *********************************************************************** -->
+<div class="doc_section">
+ <a name="overview"><b>Overview</b></a>
+</div>
+<!-- *********************************************************************** -->
+
+<div class="doc_text">
+
+<p>Welcome to LLVM! In order to get started, you first need to know some
+basic information.</p>
+
+<p>First, LLVM comes in three pieces. The first piece is the LLVM
+suite. This contains all of the tools, libraries, and header files
+needed to use the low level virtual machine. It contains an
+assembler, disassembler, bitcode analyzer and bitcode optimizer. It
+also contains basic regression tests that can be used to test the LLVM
+tools and the GCC front end.</p>
+
+<p>The second piece is the GCC front end. This component provides a version of
+GCC that compiles C and C++ code into LLVM bitcode. Currently, the GCC front
+end uses the GCC parser to convert code to LLVM. Once
+compiled into LLVM bitcode, a program can be manipulated with the LLVM tools
+from the LLVM suite.</p>
+
+<p>
+There is a third, optional piece called Test Suite. It is a suite of programs
+with a testing harness that can be used to further test LLVM's functionality
+and performance.
+</p>
+
+</div>
+
+<!-- *********************************************************************** -->
+<div class="doc_section">
+ <a name="quickstart"><b>Getting Started Quickly (A Summary)</b></a>
+</div>
+<!-- *********************************************************************** -->
+
+<div class="doc_text">
+
+<p>Here's the short story for getting up and running quickly with LLVM:</p>
+
+<ol>
+ <li>Read the documentation.</li>
+ <li>Read the documentation.</li>
+ <li>Remember that you were warned twice about reading the documentation.</li>
+ <li>Install the llvm-gcc-4.2 front end if you intend to compile C or C++
+ (see <a href="#installcf">Install the GCC Front End</a> for details):</li>
<ol>
- <li>Install the C front end:
- <ol>
- <li><tt>cd <i>where-you-want-the-C-front-end-to-live</i></tt>
- <li><tt>gunzip --stdout cfrontend.<i>platform</i>.tar.gz | tar -xvf
- -</tt>
- </ol>
-
- <p>
-
- <li>Get the Source Code
- <ul>
- <li>With the distributed files:
- <ol>
- <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
- <li><tt>gunzip --stdout llvm.tar.gz | tar -xvf -</tt>
- <li><tt>gunzip --stdout cfrontend.<i>platform</i>.tar.gz | tar
- -xvf -</tt>
- <li><tt>cd llvm</tt>
- </ol>
-
- <p>
-
- <li>With anonymous CVS access:
- <ol>
- <li>Find the path to the CVS repository containing LLVM (we'll
- call this <i>CVSROOTDIR</i>).
- <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
- <li><tt>cvs -d <i>CVSROOTDIR</i> checkout llvm</tt>
- <li><tt>cd llvm</tt>
- </ol>
- </ul>
- </ul>
-
- <p>
-
- <li>Configure the LLVM Build Environment
- <ol>
- <li>Run <tt>configure</tt> to configure the Makefiles and header
- files for the default platform.
- Useful options include:
- <ul>
- <li><tt>--with-objroot=<i>directory</i></tt>
- <br>
- Specify where object files should be placed during the
- build.
-
- <li><tt>--with-llvmgccdir=<i>directory</i></tt>
- <br>
- Specify where the LLVM C frontend is going to be installed.
- </ul>
- </ol>
-
- <p>
-
- <li>Build the LLVM Suite
- <ol>
- <li>Set your LLVM_LIB_SEARCH_PATH environment variable.
- <li><tt>gmake -k |& tee gnumake.out
- # this is csh or tcsh syntax</tt>
- </ol>
-
- <p>
-
- </ol>
-
- <p>See <a href="#environment">Setting Up Your Environment</a> on tips to
- simplify working with the LLVM front-end and compiled tools. See the
- other sub-sections below for other useful details in working with LLVM,
- or go straight to <a href="#layout">Program Layout</a> to learn about the
- layout of the source code tree. For information on building the C front
- end yourself, see <a href="#cfront">Compiling the LLVM C Front End</a> for
- information.
-
- <!------------------------------------------------------------------------->
- <h3><a name="terminology">Terminology and Notation</a></h3>
- <!------------------------------------------------------------------------->
-
- <p>Throughout this manual, the following names are used to denote paths
- specific to the local system and working environment. <i>These are not
- environment variables you need to set but just strings used in the rest
- of this document below</i>. In any of the examples below, simply replace
- each of these names with the appropriate pathname on your local system.
- All these paths are absolute:</p>
- <dl compact>
- <dt>CVSROOTDIR
- <dd>
- This is the path for the CVS repository containing the LLVM source
- code. Ask the person responsible for your local LLVM installation to
- give you this path.
- <p>
-
- <dt>OBJ_ROOT
- <dd>
- This is the top level directory for where the LLVM suite object files
- will be placed during the build.
- <p>
-
- <dt>LLVMGCCDIR
- <dd>
- This is the pathname to the location where the LLVM C Front End will
- be installed. Note that the C front end does not need to be installed
- during the LLVM suite build; you will just need to know where it will
- go for configuring the build system and running the test suite later.
- <p>
- For the pre-built C front end binaries, the LLVMGCCDIR is
- <tt>cfrontend/<i>platform</i>/llvm-gcc</tt>.
-
- <dt>GCCSRC
- <dd>
- This is the pathname of the directory where the LLVM C front end source
- code can be found.
- <p>
-
- <dt>GCCOBJ
- <dd>
- This is the pathname of the directory where the LLVM C front end object
- code will be placed during the build. It can be safely removed once
- the build is complete.
- </dl>
-
- <!------------------------------------------------------------------------->
- <h3><a name="environment">Setting Up Your Environment</a></h3>
- <!------------------------------------------------------------------------->
-
- <p>
- In order to compile and use LLVM, you will need to set some environment
- variables. There are also some shell aliases which you may find useful.
- You can set these on the command line, or better yet, set them in your
- <tt>.cshrc</tt> or <tt>.profile</tt>.
-
- <dl compact>
- <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt><i>LLVMGCCDIR</i>/llvm-gcc/bytecode-libs</tt>
- <dd>
- This environment variable helps the LLVM C front end find bytecode
- libraries that it will need for compilation.
- <p>
-
- <dt>alias llvmgcc <i>LLVMGCCDIR</i><tt>/bin/llvm-gcc</tt>
- <dd>
- This alias allows you to use the LLVM C front end without putting it in
- your <tt>PATH</tt> or typing in its complete pathname.
- </dl>
-
- <!------------------------------------------------------------------------->
- <h3><a name="unpack">Unpacking the LLVM Archives</a></h3>
- <!------------------------------------------------------------------------->
-
- <p>
- If you have the LLVM distribution, you will need to unpack it before you
- can begin to compile it. LLVM is distributed as a set of four files. Each
- file is a TAR archive that is compressed with the gzip program.
- </p>
-
- <p> The four files are as follows:
- <dl compact>
- <dt>llvm.tar.gz
- <dd>This is the source code to the LLVM suite.
- <p>
-
- <dt>cfrontend.sparc.tar.gz
- <dd>This is the binary release of the C front end for Solaris/Sparc.
- <p>
-
- <dt>cfrontend.x86.tar.gz
- <dd>This is the binary release of the C front end for Linux/x86.
- <p>
-
- <dt>cfrontend-src.tar.gz
- <dd>This is the source code release of the C front end.
- <p>
- </dl>
-
- <!------------------------------------------------------------------------->
- <h3><a name="checkout">Checkout LLVM from CVS</a></h3>
- <!------------------------------------------------------------------------->
-
- <p>If you have access to our CVS repository, you can get a fresh copy of
- the entire source code. All you need to do is check it out from CVS as
- follows:
- <ul>
- <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
- <li><tt>cvs -d <i>CVSROOTDIR</i> checkout llvm</tt></p>
- </ul>
-
- <p>This will create an '<tt>llvm</tt>' directory in the current
- directory and fully populate it with the LLVM source code, Makefiles,
- test directories, and local copies of documentation files.</p>
-
- <p>
- Note that the C front end is not included in the CVS repository. You
- should have either downloaded the source, or better yet, downloaded the
- binary distribution for your platform.
- </p>
-
- <!------------------------------------------------------------------------->
- <h3><a name="installcf">Install the C Front End</a></h3>
- <!------------------------------------------------------------------------->
-
- <p>
- Before configuring and compiling the LLVM suite, it is best to extract the
- LLVM C front end. While not used in building, the C front end is used by
- the LLVM test suite, and its location must be given to the
- <tt>configure</tt> script before the LLVM suite can be built.
- </p>
-
- <p>
- To install the C front end, do the following:
+ <li><tt>cd <i>where-you-want-the-C-front-end-to-live</i></tt></li>
+ <li><tt>gunzip --stdout llvm-gcc-4.2-<i>version</i>-<i>platform</i>.tar.gz | tar -xvf -</tt></li>
+ <li><tt><i>install-binutils-binary-from-MinGW</i></tt> (Windows only)</li>
+ <li>Note: If the binary extension is "<tt>.bz</tt>" use <tt>bunzip2</tt> instead of <tt>gunzip</tt>.</li>
+ <li>Note: On Windows, use <a href="http://www.7-zip.org">7-Zip</a> or a similar archiving tool.</li>
+ <li>Add <tt>llvm-gcc</tt>'s "<tt>bin</tt>" directory to your <tt>PATH</tt> environment variable.</li>
+ </ol></li>
+
+ <li>Get the LLVM Source Code
+ <ul>
+ <li>With the distributed files (or use <a href="#checkout">SVN</a>):
<ol>
- <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt>
- <li><tt>gunzip --stdout cfrontend.<i>platform</i>.tar.gz | tar -xvf
- -</tt>
- </ol>
+ <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
+ <li><tt>gunzip --stdout llvm-<i>version</i>.tar.gz | tar -xvf -</tt>
+ </ol></li>
- <!------------------------------------------------------------------------->
- <h3><a name="config">Local LLVM Configuration</a></h3>
- <!------------------------------------------------------------------------->
+ </ul></li>
- <p>Once checked out from the CVS repository, the LLVM suite source code
- must be configured via the <tt>configure</tt> script. This script sets
- variables in <tt>llvm/Makefile.config</tt> and
- <tt>llvm/include/Config/config.h</tt>.
-
- <p>
- The following environment variables are used by the <tt>configure</tt>
- script to configure the build system:
- </p>
-
- <table border=1>
- <tr>
- <th>Variable</th>
- <th>
- Purpose
- </th>
- </tr>
-
- <tr>
- <td>CC</td>
- <td>
- Tells <tt>configure</tt> which C compiler to use. By default,
- <tt>configure</tt> will look for the first GCC compiler in
- <tt>PATH</tt>. Use this variable to override
- <tt>configure</tt>'s default behavior.
- </td>
- </tr>
-
- <tr>
- <td>CXX</td>
- <td>
- Tells <tt>configure</tt> which C++ compiler to use. By default,
- <tt>configure</tt> will look for the first GCC compiler in
- <tt>PATH</tt>. Use this variable to override
- <tt>configure</tt>'s default behavior.
- </td>
- </tr>
- </table>
+ <li><b>[Optional]</b> Get the Test Suite Source Code
+ <ul>
+ <li>With the distributed files (or use <a href="#checkout">SVN</a>):
+ <ol>
+ <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
+ <li><tt>cd llvm/projects</tt>
+ <li><tt>gunzip --stdout llvm-test-<i>version</i>.tar.gz | tar -xvf -</tt>
+ <li><tt>mv llvm-test-<i>version</i> test-suite</tt>
+ </ol></li>
+
+ </ul></li>
+
+
+ <li>Configure the LLVM Build Environment
+ <ol>
+ <li><tt>cd <i>where-you-want-to-build-llvm</i></tt></li>
+ <li><tt><i>/path/to/llvm/</i>configure [options]</tt><br>
+ Some common options:
+
+ <ul>
+ <li><tt>--prefix=<i>directory</i></tt>
+ <p>Specify for <i>directory</i> the full pathname of where you
+ want the LLVM tools and libraries to be installed (default
+ <tt>/usr/local</tt>).</p></li>
+ <li><tt>--with-llvmgccdir=<i>directory</i></tt>
+ <p>Optionally, specify for <i>directory</i> the full pathname of the
+ C/C++ front end installation to use with this LLVM configuration. If
+ not specified, the PATH will be searched. This is only needed if you
+ want to run test-suite or do some special kinds of LLVM builds.</p></li>
+ <li><tt>--enable-spec2000=<i>directory</i></tt>
+ <p>Enable the SPEC2000 benchmarks for testing. The SPEC2000
+ benchmarks should be available in
+ <tt><i>directory</i></tt>.</p></li>
+ </ul>
+ </ol></li>
+
+ <li>Build the LLVM Suite:
+ <ol>
+ <li><tt>gmake -k |& tee gnumake.out
+ # this is csh or tcsh syntax</tt></li>
+ <li>If you get an "internal compiler error (ICE)" or test failures, see
+ <a href="#brokengcc">below</a>.</li>
+ </ol>
+
+</ol>
+
+<p>Consult the <a href="#starting">Getting Started with LLVM</a> section for
+detailed information on configuring and compiling LLVM. See <a
+href="#environment">Setting Up Your Environment</a> for tips that simplify
+working with the GCC front end and LLVM tools. Go to <a href="#layout">Program
+Layout</a> to learn about the layout of the source code tree.</p>
+
+</div>
+
+<!-- *********************************************************************** -->
+<div class="doc_section">
+ <a name="requirements"><b>Requirements</b></a>
+</div>
+<!-- *********************************************************************** -->
+
+<div class="doc_text">
+
+<p>Before you begin to use the LLVM system, review the requirements given below.
+This may save you some trouble by knowing ahead of time what hardware and
+software you will need.</p>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="hardware"><b>Hardware</b></a>
+</div>
+
+<div class="doc_text">
+
+<p>LLVM is known to work on the following platforms:</p>
+
+<table cellpadding="3" summary="Known LLVM platforms">
+<tr>
+ <th>OS</th>
+ <th>Arch</th>
+ <th>Compilers</th>
+</tr>
+<tr>
+ <td>AuroraUX</td>
+ <td>x86<sup><a href="#pf_1">1</a></sup></td>
+ <td>GCC</td>
+</tr>
+<tr>
+ <td>Linux</td>
+ <td>x86<sup><a href="#pf_1">1</a></sup></td>
+ <td>GCC</td>
+</tr>
+<tr>
+ <td>Linux</td>
+ <td>amd64</td>
+ <td>GCC</td>
+</tr>
+<tr>
+ <td>Solaris</td>
+ <td>V9 (Ultrasparc)</td>
+ <td>GCC</td>
+</tr>
+<tr>
+ <td>FreeBSD</td>
+ <td>x86<sup><a href="#pf_1">1</a></sup></td>
+ <td>GCC</td>
+</tr>
+<tr>
+ <td>FreeBSD</td>
+ <td>amd64</td>
+ <td>GCC</td>
+</tr>
+<tr>
+ <td>MacOS X<sup><a href="#pf_2">2</a></sup></td>
+ <td>PowerPC</td>
+ <td>GCC</td>
+</tr>
+<tr>
+ <td>MacOS X<sup><a href="#pf_2">2</a>,<a href="#pf_9">9</a></sup></td>
+ <td>x86</td>
+ <td>GCC</td>
+</tr>
+<tr>
+ <td>Cygwin/Win32</td>
+ <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_8">8</a>,
+ <a href="#pf_11">11</a></sup></td>
+ <td>GCC 3.4.X, binutils 2.20</td>
+</tr>
+<tr>
+ <td>MinGW/Win32</td>
+ <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_6">6</a>,
+ <a href="#pf_8">8</a>, <a href="#pf_10">10</a></sup></td>
+ <td>GCC 3.4.X, binutils 2.20</td>
+</tr>
+</table>
+
+<p>LLVM has partial support for the following platforms:</p>
+
+<table summary="LLVM partial platform support">
+<tr>
+ <th>OS</th>
+ <th>Arch</th>
+ <th>Compilers</th>
+</tr>
+<tr>
+ <td>Windows</td>
+ <td>x86<sup><a href="#pf_1">1</a></sup></td>
+ <td>Visual Studio 2005 SP1 or higher<sup><a href="#pf_4">4</a>,<a href="#pf_5">5</a></sup></td>
+<tr>
+ <td>AIX<sup><a href="#pf_3">3</a>,<a href="#pf_4">4</a></sup></td>
+ <td>PowerPC</td>
+ <td>GCC</td>
+</tr>
+<tr>
+ <td>Linux<sup><a href="#pf_3">3</a>,<a href="#pf_5">5</a></sup></td>
+ <td>PowerPC</td>
+ <td>GCC</td>
+</tr>
+
+<tr>
+ <td>Linux<sup><a href="#pf_7">7</a></sup></td>
+ <td>Alpha</td>
+ <td>GCC</td>
+</tr>
+<tr>
+ <td>Linux<sup><a href="#pf_7">7</a></sup></td>
+ <td>Itanium (IA-64)</td>
+ <td>GCC</td>
+</tr>
+<tr>
+ <td>HP-UX<sup><a href="#pf_7">7</a></sup></td>
+ <td>Itanium (IA-64)</td>
+ <td>HP aCC</td>
+</tr>
+</table>
+
+<p><b>Notes:</b></p>
+
+<div class="doc_notes">
+<ol>
+<li><a name="pf_1">Code generation supported for Pentium processors and
+up</a></li>
+<li><a name="pf_2">Code generation supported for 32-bit ABI only</a></li>
+<li><a name="pf_3">No native code generation</a></li>
+<li><a name="pf_4">Build is not complete: one or more tools do not link or function</a></li>
+<li><a name="pf_5">The GCC-based C/C++ frontend does not build</a></li>
+<li><a name="pf_6">The port is done using the MSYS shell.</a></li>
+<li><a name="pf_7">Native code generation exists but is not complete.</a></li>
+<li><a name="pf_8">Binutils 2.20 or later is required to build the assembler
+ generated by LLVM properly.</a></li>
+<li><a name="pf_9">XCode 2.5 and gcc 4.0.1</a> (Apple Build 5370) will trip
+ internal LLVM assert messages when compiled for Release at optimization
+ levels greater than 0 (i.e., <i>"-O1"</i> and higher).
+ Add <i>OPTIMIZE_OPTION="-O0"</i> to the build command line
+ if compiling for LLVM Release or bootstrapping the LLVM toolchain.</li>
+<li><a name="pf_10">For MSYS/MinGW on Windows, be sure to install the MSYS
+ version of the perl package, and be sure it appears in your path
+ before any Windows-based versions such as Strawberry Perl and
+ ActivePerl, as these have Windows-specifics that will cause the
+ build to fail.</a></li>
+<li><a name="pf_11">In general, LLVM modules requiring dynamic linking can
+ not be built on Windows. However, you can build LLVM tools using
+ <i>"make tools-only"</i>.</li>
+</ol>
+</div>
+
+<p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug
+mode, depending on the system (it is so large because of all the debugging
+information and the fact that the libraries are statically linked into multiple
+tools). If you do not need many of the tools and you are space-conscious, you
+can pass <tt>ONLY_TOOLS="tools you need"</tt> to make. The Release build
+requires considerably less space.</p>
+
+<p>The LLVM suite <i>may</i> compile on other platforms, but it is not
+guaranteed to do so. If compilation is successful, the LLVM utilities should be
+able to assemble, disassemble, analyze, and optimize LLVM bitcode. Code
+generation should work as well, although the generated native code may not work
+on your platform.</p>
+
+<p>The GCC front end is not very portable at the moment. If you want to get it
+to work on another platform, you can download a copy of the source and <a
+href="GCCFEBuildInstrs.html">try to compile it</a> on your platform.</p>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="software"><b>Software</b></a></div>
+<div class="doc_text">
+ <p>Compiling LLVM requires that you have several software packages
+ installed. The table below lists those required packages. The Package column
+ is the usual name for the software package that LLVM depends on. The Version
+ column provides "known to work" versions of the package. The Notes column
+ describes how LLVM uses the package and provides other details.</p>
+ <table summary="Packages required to compile LLVM">
+ <tr><th>Package</th><th>Version</th><th>Notes</th></tr>
+
+ <tr>
+ <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td>
+ <td>3.79, 3.79.1</td>
+ <td>Makefile/build processor</td>
+ </tr>
+
+ <tr>
+ <td><a href="http://gcc.gnu.org">GCC</a></td>
+ <td>3.4.2</td>
+ <td>C/C++ compiler<sup><a href="#sf1">1</a></sup></td>
+ </tr>
+
+ <tr>
+ <td><a href="http://www.gnu.org/software/texinfo">TeXinfo</a></td>
+ <td>4.5</td>
+ <td>For building the CFE</td>
+ </tr>
+
+ <tr>
+ <td><a href="http://subversion.tigris.org/project_packages.html">SVN</a></td>
+ <td>≥1.3</td>
+ <td>Subversion access to LLVM<sup><a href="#sf2">2</a></sup></td>
+ </tr>
+
+ <tr>
+ <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td>
+ <td>1.4.2</td>
+ <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
+ </tr>
+
+ <tr>
+ <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td>
+ <td>8.3, 8.4</td>
+ <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
+ </tr>
+
+ <tr>
+ <td><a href="http://expect.nist.gov/">expect</a></td>
+ <td>5.38.0</td>
+ <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
+ </tr>
+
+ <tr>
+ <td><a href="http://www.perl.com/download.csp">perl</a></td>
+ <td>≥5.6.0</td>
+ <td>Nightly tester, utilities</td>
+ </tr>
+
+ <tr>
+ <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a>
+ <td>1.4</td>
+ <td>Macro processor for configuration<sup><a href="#sf4">4</a></sup></td>
+ </tr>
+
+ <tr>
+ <td><a href="http://www.gnu.org/software/autoconf">GNU Autoconf</a></td>
+ <td>2.60</td>
+ <td>Configuration script builder<sup><a href="#sf4">4</a></sup></td>
+ </tr>
+
+ <tr>
+ <td><a href="http://www.gnu.org/software/automake">GNU Automake</a></td>
+ <td>1.9.6</td>
+ <td>aclocal macro generator<sup><a href="#sf4">4</a></sup></td>
+ </tr>
+
+ <tr>
+ <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td>
+ <td>1.5.22</td>
+ <td>Shared library manager<sup><a href="#sf4">4</a></sup></td>
+ </tr>
+
+ </table>
+
+ <p><b>Notes:</b></p>
+ <div class="doc_notes">
+ <ol>
+ <li><a name="sf1">Only the C and C++ languages are needed so there's no
+ need to build the other languages for LLVM's purposes.</a> See
+ <a href="#brokengcc">below</a> for specific version info.</li>
+ <li><a name="sf2">You only need Subversion if you intend to build from the
+ latest LLVM sources. If you're working from a release distribution, you
+ don't need Subversion.</a></li>
+ <li><a name="sf3">Only needed if you want to run the automated test
+ suite in the <tt>llvm/test</tt> directory.</a></li>
+ <li><a name="sf4">If you want to make changes to the configure scripts,
+ you will need GNU autoconf (2.60), and consequently, GNU M4 (version 1.4
+ or higher). You will also need automake (1.9.6). We only use aclocal
+ from that package.</a></li>
+ </ol>
+ </div>
+
+ <p>Additionally, your compilation host is expected to have the usual
+ plethora of Unix utilities. Specifically:</p>
+ <ul>
+ <li><b>ar</b> - archive library builder</li>
+ <li><b>bzip2*</b> - bzip2 command for distribution generation</li>
+ <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
+ <li><b>chmod</b> - change permissions on a file</li>
+ <li><b>cat</b> - output concatenation utility</li>
+ <li><b>cp</b> - copy files</li>
+ <li><b>date</b> - print the current date/time </li>
+ <li><b>echo</b> - print to standard output</li>
+ <li><b>egrep</b> - extended regular expression search utility</li>
+ <li><b>find</b> - find files/dirs in a file system</li>
+ <li><b>grep</b> - regular expression search utility</li>
+ <li><b>gzip*</b> - gzip command for distribution generation</li>
+ <li><b>gunzip*</b> - gunzip command for distribution checking</li>
+ <li><b>install</b> - install directories/files </li>
+ <li><b>mkdir</b> - create a directory</li>
+ <li><b>mv</b> - move (rename) files</li>
+ <li><b>ranlib</b> - symbol table builder for archive libraries</li>
+ <li><b>rm</b> - remove (delete) files and directories</li>
+ <li><b>sed</b> - stream editor for transforming output</li>
+ <li><b>sh</b> - Bourne shell for make build scripts</li>
+ <li><b>tar</b> - tape archive for distribution generation</li>
+ <li><b>test</b> - test things in file system</li>
+ <li><b>unzip*</b> - unzip command for distribution checking</li>
+ <li><b>zip*</b> - zip command for distribution generation</li>
+ </ul>
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="brokengcc">Broken versions of GCC and other tools</a>
+</div>
+
+<div class="doc_text">
+
+<p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
+bugs in the compiler. In particular, several versions of GCC crash when trying
+to compile LLVM. We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1
+successfully with them (however, see important notes below). Other versions
+of GCC will probably work as well. GCC versions listed
+here are known to not work. If you are using one of these versions, please try
+to upgrade your GCC to something more recent. If you run into a problem with a
+version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
+us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version
+of GCC you are using.
+</p>
+
+<p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
+problems in the STL that effectively prevent it from compiling LLVM.
+</p>
+
+<p><b>GCC 3.2.2 and 3.2.3</b>: These versions of GCC fails to compile LLVM with
+a bogus template error. This was fixed in later GCCs.</p>
+
+<p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
+href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
+the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
+
+<p><b>Cygwin GCC 3.3.3</b>: The version of GCC 3.3.3 commonly shipped with
+ Cygwin does not work. Please <a href="GCCFEBuildInstrs.html#cygwin">upgrade
+ to a newer version</a> if possible.</p>
+<p><b>SuSE GCC 3.3.3</b>: The version of GCC 3.3.3 shipped with SuSE 9.1 (and
+ possibly others) does not compile LLVM correctly (it appears that exception
+ handling is broken in some cases). Please download the FSF 3.3.3 or upgrade
+ to a newer version of GCC.</p>
+<p><b>GCC 3.4.0 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
+ code generator, causing an infinite loop in the llvm-gcc build when built
+ with optimizations enabled (i.e. a release build).</p>
+<p><b>GCC 3.4.2 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
+ code generator at -O3, as with 3.4.0. However gcc 3.4.2 (unlike 3.4.0)
+ correctly compiles LLVM at -O2. A work around is to build release LLVM
+ builds with "make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ..."</p>
+<p><b>GCC 3.4.x on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1056">
+ miscompiles portions of LLVM</a>.</p>
+<p><b>GCC 3.4.4 (CodeSourcery ARM 2005q3-2)</b>: this compiler miscompiles LLVM
+ when building with optimizations enabled. It appears to work with
+ "<tt>make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O1</tt>" or build a debug
+ build.</p>
+<p><b>IA-64 GCC 4.0.0</b>: The IA-64 version of GCC 4.0.0 is known to
+ miscompile LLVM.</p>
+<p><b>Apple Xcode 2.3</b>: GCC crashes when compiling LLVM at -O3 (which is the
+ default with ENABLE_OPTIMIZED=1. To work around this, build with
+ "ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2".</p>
+<p><b>GCC 4.1.1</b>: GCC fails to build LLVM with template concept check errors
+ compiling some files. At the time of this writing, GCC mainline (4.2)
+ did not share the problem.</p>
+<p><b>GCC 4.1.1 on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1063">
+ miscompiles portions of LLVM</a> when compiling llvm itself into 64-bit
+ code. LLVM will appear to mostly work but will be buggy, e.g. failing
+ portions of its testsuite.</p>
+<p><b>GCC 4.1.2 on OpenSUSE</b>: Seg faults during libstdc++ build and on x86_64
+platforms compiling md5.c gets a mangled constant.</p>
+<p><b>GCC 4.1.2 (20061115 (prerelease) (Debian 4.1.1-21)) on Debian</b>: Appears
+to miscompile parts of LLVM 2.4. One symptom is ValueSymbolTable complaining
+about symbols remaining in the table on destruction.</p>
+<p><b>GCC 4.1.2 20071124 (Red Hat 4.1.2-42)</b>: Suffers from the same symptoms
+as the previous one. It appears to work with ENABLE_OPTIMIZED=0 (the default).</p>
+<p><b>Cygwin GCC 4.3.2 20080827 (beta) 2</b>:
+ Users <a href="http://llvm.org/PR4145">reported</a> various problems related
+ with link errors when using this GCC version.</p>
+<p><b>Debian GCC 4.3.2 on X86</b>: Crashes building some files in LLVM 2.6.</p>
+<p><b>GCC 4.3.3 (Debian 4.3.3-10) on ARM</b>: Miscompiles parts of LLVM 2.6
+when optimizations are turned on. The symptom is an infinite loop in
+FoldingSetImpl::RemoveNode while running the code generator.</p>
+<p><b>GCC 4.3.5 and GCC 4.4.5 on ARM</b>: These can miscompile <tt>value >>
+1</tt> even at -O0. A test failure in <tt>test/Assembler/alignstack.ll</tt> is
+one symptom of the problem.
+<p><b>GNU ld 2.16.X</b>. Some 2.16.X versions of the ld linker will produce very
+long warning messages complaining that some ".gnu.linkonce.t.*" symbol was
+defined in a discarded section. You can safely ignore these messages as they are
+erroneous and the linkage is correct. These messages disappear using ld
+2.17.</p>
+
+<p><b>GNU binutils 2.17</b>: Binutils 2.17 contains <a
+href="http://sourceware.org/bugzilla/show_bug.cgi?id=3111">a bug</a> which
+causes huge link times (minutes instead of seconds) when building LLVM. We
+recommend upgrading to a newer version (2.17.50.0.4 or later).</p>
+
+<p><b>GNU Binutils 2.19.1 Gold</b>: This version of Gold contained
+<a href="http://sourceware.org/bugzilla/show_bug.cgi?id=9836">a bug</a>
+which causes intermittent failures when building LLVM with position independent
+code. The symptom is an error about cyclic dependencies. We recommend
+upgrading to a newer version of Gold.</p>
+
+</div>
+
+
+
+<!-- *********************************************************************** -->
+<div class="doc_section">
+ <a name="starting"><b>Getting Started with LLVM</b></a>
+</div>
+<!-- *********************************************************************** -->
+
+<div class="doc_text">
+
+<p>The remainder of this guide is meant to get you up and running with
+LLVM and to give you some basic information about the LLVM environment.</p>
+
+<p>The later sections of this guide describe the <a
+href="#layout">general layout</a> of the the LLVM source tree, a <a
+href="#tutorial">simple example</a> using the LLVM tool chain, and <a
+href="#links">links</a> to find more information about LLVM or to get
+help via e-mail.</p>
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="terminology">Terminology and Notation</a>
+</div>
+
+<div class="doc_text">
+
+<p>Throughout this manual, the following names are used to denote paths
+specific to the local system and working environment. <i>These are not
+environment variables you need to set but just strings used in the rest
+of this document below</i>. In any of the examples below, simply replace
+each of these names with the appropriate pathname on your local system.
+All these paths are absolute:</p>
+
+<dl>
+ <dt>SRC_ROOT
+ <dd>
+ This is the top level directory of the LLVM source tree.
+ <br><br>
- <p>
- The following options can be used to set or enable LLVM specific options:
- </p>
+ <dt>OBJ_ROOT
+ <dd>
+ This is the top level directory of the LLVM object tree (i.e. the
+ tree where object files and compiled programs will be placed. It
+ can be the same as SRC_ROOT).
+ <br><br>
- <dl compact>
- <dt><i>--with-objroot=OBJ_ROOT</i>
+ <dt>LLVMGCCDIR
<dd>
- Path to the directory where
- object files, libraries, and executables should be placed.
- If this is set to <tt>.</tt>, then the object files will be placed
- within the source code tree. If left unspecified, the default value is
- the following:
- <ul>
- <li>
- If the USER environment variable is specified and the directory
- <tt>/localhome/$USER</tt> exists, then the default value is
- <tt>/localhome/$USER</tt>.
-
- <li>
- Otherwise, the default value is <tt>.</tt>.
- </ul>
- (See the Section on <a href=#objfiles>
- The Location of LLVM Object Files</a>
- for more information.)
- <p>
- <dt><i>--with-llvmgccdir=LLVMGCCDIR</i>
+ This is where the LLVM GCC Front End is installed.
+ <p>
+ For the pre-built GCC front end binaries, the LLVMGCCDIR is
+ <tt>llvm-gcc/<i>platform</i>/llvm-gcc</tt>.
+</dl>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="environment">Setting Up Your Environment</a>
+</div>
+
+<div class="doc_text">
+
+<p>
+In order to compile and use LLVM, you may need to set some environment
+variables.
+
+<dl>
+ <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bitcode/libs</tt></dt>
+ <dd>[Optional] This environment variable helps LLVM linking tools find the
+ locations of your bitcode libraries. It is provided only as a
+ convenience since you can specify the paths using the -L options of the
+ tools and the C/C++ front-end will automatically use the bitcode files
+ installed in its
+ <tt>lib</tt> directory.</dd>
+</dl>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="unpack">Unpacking the LLVM Archives</a>
+</div>
+
+<div class="doc_text">
+
+<p>
+If you have the LLVM distribution, you will need to unpack it before you
+can begin to compile it. LLVM is distributed as a set of two files: the LLVM
+suite and the LLVM GCC front end compiled for your platform. There is an
+additional test suite that is optional. Each file is a TAR archive that is
+compressed with the gzip program.
+</p>
+
+<p>The files are as follows, with <em>x.y</em> marking the version number:
+<dl>
+ <dt><tt>llvm-x.y.tar.gz</tt></dt>
+ <dd>Source release for the LLVM libraries and tools.<br></dd>
+
+ <dt><tt>llvm-test-x.y.tar.gz</tt></dt>
+ <dd>Source release for the LLVM test-suite.</dd>
+
+ <dt><tt>llvm-gcc-4.2-x.y.source.tar.gz</tt></dt>
+ <dd>Source release of the llvm-gcc-4.2 front end. See README.LLVM in the root
+ directory for build instructions.<br></dd>
+
+ <dt><tt>llvm-gcc-4.2-x.y-platform.tar.gz</tt></dt>
+ <dd>Binary release of the llvm-gcc-4.2 front end for a specific platform.<br></dd>
+
+</dl>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="checkout">Checkout LLVM from Subversion</a>
+</div>
+
+<div class="doc_text">
+
+<p>If you have access to our Subversion repository, you can get a fresh copy of
+the entire source code. All you need to do is check it out from Subversion as
+follows:</p>
+
+<ul>
+ <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
+ <li>Read-Only: <tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li>
+ <li>Read-Write:<tt>svn co https://user@llvm.org/svn/llvm-project/llvm/trunk
+ llvm</tt></li>
+</ul>
+
+
+<p>This will create an '<tt>llvm</tt>' directory in the current
+directory and fully populate it with the LLVM source code, Makefiles,
+test directories, and local copies of documentation files.</p>
+
+<p>If you want to get a specific release (as opposed to the most recent
+revision), you can checkout it from the '<tt>tags</tt>' directory (instead of
+'<tt>trunk</tt>'). The following releases are located in the following
+subdirectories of the '<tt>tags</tt>' directory:</p>
+
+<ul>
+<li>Release 2.8: <b>RELEASE_28</b></li>
+<li>Release 2.7: <b>RELEASE_27</b></li>
+<li>Release 2.6: <b>RELEASE_26</b></li>
+<li>Release 2.5: <b>RELEASE_25</b></li>
+<li>Release 2.4: <b>RELEASE_24</b></li>
+<li>Release 2.3: <b>RELEASE_23</b></li>
+<li>Release 2.2: <b>RELEASE_22</b></li>
+<li>Release 2.1: <b>RELEASE_21</b></li>
+<li>Release 2.0: <b>RELEASE_20</b></li>
+<li>Release 1.9: <b>RELEASE_19</b></li>
+<li>Release 1.8: <b>RELEASE_18</b></li>
+<li>Release 1.7: <b>RELEASE_17</b></li>
+<li>Release 1.6: <b>RELEASE_16</b></li>
+<li>Release 1.5: <b>RELEASE_15</b></li>
+<li>Release 1.4: <b>RELEASE_14</b></li>
+<li>Release 1.3: <b>RELEASE_13</b></li>
+<li>Release 1.2: <b>RELEASE_12</b></li>
+<li>Release 1.1: <b>RELEASE_11</b></li>
+<li>Release 1.0: <b>RELEASE_1</b></li>
+</ul>
+
+<p>If you would like to get the LLVM test suite (a separate package as of 1.4),
+you get it from the Subversion repository:</p>
+
+<div class="doc_code">
+<pre>
+% cd llvm/projects
+% svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite
+</pre>
+</div>
+
+<p>By placing it in the <tt>llvm/projects</tt>, it will be automatically
+configured by the LLVM configure script as well as automatically updated when
+you run <tt>svn update</tt>.</p>
+
+<p>If you would like to get the GCC front end source code, you can also get it
+and build it yourself. Please follow <a href="GCCFEBuildInstrs.html">these
+instructions</a> to successfully get and build the LLVM GCC front-end.</p>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="git_mirror">GIT mirror</a>
+</div>
+
+<div class="doc_text">
+
+<p>GIT mirrors are available for a number of LLVM subprojects. These mirrors
+ sync automatically with each Subversion commit and contain all necessary
+ git-svn marks (so, you can recreate git-svn metadata locally). Note that right
+ now mirrors reflect only <tt>trunk</tt> for each project. You can do the
+ read-only GIT clone of LLVM via:
+<pre>
+% git clone http://llvm.org/git/llvm.git
+</pre>
+</p>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="installcf">Install the GCC Front End</a>
+</div>
+
+<div class="doc_text">
+
+<p>Before configuring and compiling the LLVM suite (or if you want to use just the LLVM
+GCC front end) you can optionally extract the front end from the binary distribution.
+It is used for running the LLVM test-suite and for compiling C/C++ programs. Note that
+you can optionally <a href="GCCFEBuildInstrs.html">build llvm-gcc yourself</a> after building the
+main LLVM repository.</p>
+
+<p>To install the GCC front end, do the following (on Windows, use an archival tool
+like <a href="http://www.7-zip.org">7-zip</a> that understands gzipped tars):</p>
+
+<ol>
+ <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt></li>
+ <li><tt>gunzip --stdout llvm-gcc-4.2-<i>version</i>-<i>platform</i>.tar.gz | tar -xvf
+ -</tt></li>
+</ol>
+
+<p>Once the binary is uncompressed, if you're using a *nix-based system, add a symlink for
+<tt>llvm-gcc</tt> and <tt>llvm-g++</tt> to some directory in your path. If you're using a
+Windows-based system, add the <tt>bin</tt> subdirectory of your front end installation directory
+to your <tt>PATH</tt> environment variable. For example, if you uncompressed the binary to
+<tt>c:\llvm-gcc</tt>, add <tt>c:\llvm-gcc\bin</tt> to your <tt>PATH</tt>.</p>
+
+<p>If you now want to build LLVM from source, when you configure LLVM, it will
+automatically detect <tt>llvm-gcc</tt>'s presence (if it is in your path) enabling its
+use in test-suite. Note that you can always build or install <tt>llvm-gcc</tt> at any
+point after building the main LLVM repository: just reconfigure llvm and
+test-suite will pick it up.
+</p>
+
+<p>As a convenience for Windows users, the front end binaries for MinGW/x86 include
+versions of the required w32api and mingw-runtime binaries. The last remaining step for
+Windows users is to simply uncompress the binary binutils package from
+<a href="http://mingw.org/">MinGW</a> into your front end installation directory. While the
+front end installation steps are not quite the same as a typical manual MinGW installation,
+they should be similar enough to those who have previously installed MinGW on Windows systems.</p>
+
+<p>To install binutils on Windows:</p>
+
+<ol>
+ <li><tt><i>download GNU Binutils from <a href="http://sourceforge.net/projects/mingw/files/">MinGW Downloads</a></i></tt></li>
+ <li><tt>cd <i>where-you-uncompressed-the-front-end</i></tt></li>
+ <li><tt><i>uncompress archived binutils directories (not the tar file) into the current directory</i></tt></li>
+</ol>
+
+<p>The binary versions of the LLVM GCC front end may not suit all of your needs. For
+example, the binary distribution may include an old version of a system header
+file, not "fix" a header file that needs to be fixed for GCC, or it may be linked with
+libraries not available on your system. In cases like these, you may want to try
+<a href="GCCFEBuildInstrs.html">building the GCC front end from source</a>. Thankfully,
+this is much easier now than it was in the past.</p>
+
+<p>We also do not currently support updating of the GCC front end by manually overlaying
+newer versions of the w32api and mingw-runtime binary packages that may become available
+from MinGW. At this time, it's best to think of the MinGW LLVM GCC front end binary as
+a self-contained convenience package that requires Windows users to simply download and
+uncompress the GNU Binutils binary package from the MinGW project.</p>
+
+<p>Regardless of your platform, if you discover that installing the LLVM GCC front end
+binaries is not as easy as previously described, or you would like to suggest improvements,
+please let us know how you would like to see things improved by dropping us a note on our
+<a href="http://llvm.org/docs/#maillist">mailing list</a>.</p>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="config">Local LLVM Configuration</a>
+</div>
+
+<div class="doc_text">
+
+ <p>Once checked out from the Subversion repository, the LLVM suite source
+ code must be
+configured via the <tt>configure</tt> script. This script sets variables in the
+various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and
+<tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with
+the Makefiles needed to begin building LLVM.</p>
+
+<p>The following environment variables are used by the <tt>configure</tt>
+script to configure the build system:</p>
+
+<table summary="LLVM configure script environment variables">
+ <tr><th>Variable</th><th>Purpose</th></tr>
+ <tr>
+ <td>CC</td>
+ <td>Tells <tt>configure</tt> which C compiler to use. By default,
+ <tt>configure</tt> will look for the first GCC C compiler in
+ <tt>PATH</tt>. Use this variable to override
+ <tt>configure</tt>'s default behavior.</td>
+ </tr>
+ <tr>
+ <td>CXX</td>
+ <td>Tells <tt>configure</tt> which C++ compiler to use. By default,
+ <tt>configure</tt> will look for the first GCC C++ compiler in
+ <tt>PATH</tt>. Use this variable to override
+ <tt>configure</tt>'s default behavior.</td>
+ </tr>
+</table>
+
+<p>The following options can be used to set or enable LLVM specific options:</p>
+
+<dl>
+ <dt><i>--with-llvmgccdir</i></dt>
+ <dd>Path to the LLVM C/C++ FrontEnd to be used with this LLVM configuration.
+ The value of this option should specify the full pathname of the C/C++ Front
+ End to be used. If this option is not provided, the PATH will be searched for
+ a program named <i>llvm-gcc</i> and the C/C++ FrontEnd install directory will
+ be inferred from the path found. If the option is not given, and no llvm-gcc
+ can be found in the path then a warning will be produced by
+ <tt>configure</tt> indicating this situation. LLVM may still be built with
+ the <tt>tools-only</tt> target but attempting to build the runtime libraries
+ will fail as these libraries require llvm-gcc and llvm-g++. See
+ <a href="#installcf">Install the GCC Front End</a> for details on installing
+ the C/C++ Front End. See
+ <a href="GCCFEBuildInstrs.html">Bootstrapping the LLVM C/C++ Front-End</a>
+ for details on building the C/C++ Front End.</dd>
+ <dt><i>--with-tclinclude</i></dt>
+ <dd>Path to the tcl include directory under which <tt>tclsh</tt> can be
+ found. Use this if you have multiple tcl installations on your machine and you
+ want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the
+ dejagnu based test suite in <tt>llvm/test</tt>. If you don't specify this
+ option, the LLVM configure script will search for the tcl 8.4 and 8.3
+ releases.
+ <br><br>
+ </dd>
+ <dt><i>--enable-optimized</i></dt>
+ <dd>
+ Enables optimized compilation (debugging symbols are removed
+ and GCC optimization flags are enabled). Note that this is the default
+ setting if you are using the LLVM distribution. The default behavior
+ of an Subversion checkout is to use an unoptimized build (also known as a
+ debug build).
+ <br><br>
+ </dd>
+ <dt><i>--enable-debug-runtime</i></dt>
+ <dd>
+ Enables debug symbols in the runtime libraries. The default is to strip
+ debug symbols from the runtime libraries.
+ </dd>
+ <dt><i>--enable-jit</i></dt>
+ <dd>
+ Compile the Just In Time (JIT) compiler functionality. This is not
+ available
+ on all platforms. The default is dependent on platform, so it is best
+ to explicitly enable it if you want it.
+ <br><br>
+ </dd>
+ <dt><i>--enable-targets=</i><tt>target-option</tt></dt>
+ <dd>Controls which targets will be built and linked into llc. The default
+ value for <tt>target_options</tt> is "all" which builds and links all
+ available targets. The value "host-only" can be specified to build only a
+ native compiler (no cross-compiler targets available). The "native" target is
+ selected as the target of the build host. You can also specify a comma
+ separated list of target names that you want available in llc. The target
+ names use all lower case. The current set of targets is: <br>
+ <tt>alpha, ia64, powerpc, skeleton, sparc, x86</tt>.
+ <br><br></dd>
+ <dt><i>--enable-doxygen</i></dt>
+ <dd>Look for the doxygen program and enable construction of doxygen based
+ documentation from the source code. This is disabled by default because
+ generating the documentation can take a long time and producess 100s of
+ megabytes of output.</dd>
+ <dt><i>--with-udis86</i></dt>
+ <dd>LLVM can use external disassembler library for various purposes (now it's
+ used only for examining code produced by JIT). This option will enable usage
+ of <a href="http://udis86.sourceforge.net/">udis86</a> x86 (both 32 and 64
+ bits) disassembler library.</dd>
+</dl>
+
+<p>To configure LLVM, follow these steps:</p>
+
+<ol>
+ <li><p>Change directory into the object root directory:</p>
+
+ <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
+
+ <li><p>Run the <tt>configure</tt> script located in the LLVM source
+ tree:</p>
+
+ <div class="doc_code">
+ <pre>% <i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</pre>
+ </div></li>
+</ol>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="compile">Compiling the LLVM Suite Source Code</a>
+</div>
+
+<div class="doc_text">
+
+<p>Once you have configured LLVM, you can build it. There are three types of
+builds:</p>
+
+<dl>
+ <dt>Debug Builds
<dd>
- Path to the location where the LLVM C front end binaries and
- associated libraries will be installed.
- <p>
- <dt><i>--enable-optimized</i>
+ These builds are the default when one is using an Subversion checkout and
+ types <tt>gmake</tt> (unless the <tt>--enable-optimized</tt> option was
+ used during configuration). The build system will compile the tools and
+ libraries with debugging information. To get a Debug Build using the
+ LLVM distribution the <tt>--disable-optimized</tt> option must be passed
+ to <tt>configure</tt>.
+ <br><br>
+
+ <dt>Release (Optimized) Builds
<dd>
- Enables optimized compilation (debugging symbols are removed and GCC
- optimization flags are enabled). The default is to use an unoptimized
- build (also known as a debug build).
- <p>
- <dt><i>--enable-jit</i>
+ These builds are enabled with the <tt>--enable-optimized</tt> option to
+ <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
+ <tt>gmake</tt> command line. For these builds, the build system will
+ compile the tools and libraries with GCC optimizations enabled and strip
+ debugging information from the libraries and executables it generates.
+ Note that Release Builds are default when using an LLVM distribution.
+ <br><br>
+
+ <dt>Profile Builds
<dd>
- Compile the Just In Time (JIT) functionality. This is not available
- on all platforms. The default is dependent on platform, so it is best
- to explicitly enable it if you want it.
- </dl>
-
- In addition to running <tt>configure</tt>, you must set the
- <tt>LLVM_LIB_SEARCH_PATH</tt> environment variable in your startup scripts.
- This environment variable is used to locate "system" libraries like
- "<tt>-lc</tt>" and "<tt>-lm</tt>" when linking. This variable should be set
- to the absolute path for the bytecode-libs subdirectory of the C front-end
- install, or LLVMGCCDIR/llvm-gcc/bytecode-libs. For example, one might
- set <tt>LLVM_LIB_SEARCH_PATH</tt> to
- <tt>/home/vadve/lattner/local/x86/llvm-gcc/bytecode-libs</tt> for the X86
- version of the C front-end on our research machines.<p>
-
- <!------------------------------------------------------------------------->
- <h3><a name="compile">Compiling the LLVM Suite Source Code</a></h3>
- <!------------------------------------------------------------------------->
-
- Once you have configured LLVM, you can build it. There are three types of
- builds:
-
- <dl compact>
- <dt>Debug Builds
- <dd>
- These builds are the default. They compile the tools and libraries
- with debugging information.
- <p>
-
- <dt>Release (Optimized) Builds
- <dd>
- These builds are enabled with the <tt>--enable-optimized</tt> option to
- <tt>configure</tt>. They compile the tools and libraries with GCC
- optimizer flags on and strip debugging information from the libraries
- and executables it generates.
- <p>
-
- <dt>Profile Builds
- <dd>
- These builds are for use with profiling. They compile profiling
- information into the code for use with programs like <tt>gprof</tt>.
- Profile builds must be started by setting variables on the
- <tt>gmake</tt> command line.
- </dl>
-
- Once you have LLVM configured, you can build it by entering the top level
- <tt>llvm</tt> directory and issuing the following command:
- <p>
- <tt>gmake</tt>
+ These builds are for use with profiling. They compile profiling
+ information into the code for use with programs like <tt>gprof</tt>.
+ Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
+ on the <tt>gmake</tt> command line.
+</dl>
+
+<p>Once you have LLVM configured, you can build it by entering the
+<i>OBJ_ROOT</i> directory and issuing the following command:</p>
+
+<div class="doc_code"><pre>% gmake</pre></div>
+
+<p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
+are using a version of GCC that is known not to compile LLVM.</p>
+
+<p>
+If you have multiple processors in your machine, you may wish to use some of
+the parallel build options provided by GNU Make. For example, you could use the
+command:</p>
+
+<div class="doc_code"><pre>% gmake -j2</pre></div>
+
+<p>There are several special targets which are useful when working with the LLVM
+source code:</p>
+
+<dl>
+ <dt><tt>gmake clean</tt>
+ <dd>
+ Removes all files generated by the build. This includes object files,
+ generated C/C++ files, libraries, and executables.
+ <br><br>
+
+ <dt><tt>gmake dist-clean</tt>
+ <dd>
+ Removes everything that <tt>gmake clean</tt> does, but also removes files
+ generated by <tt>configure</tt>. It attempts to return the source tree to the
+ original state in which it was shipped.
+ <br><br>
+
+ <dt><tt>gmake install</tt>
+ <dd>
+ Installs LLVM header files, libraries, tools, and documentation in a
+ hierarchy
+ under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
+ defaults to <tt>/usr/local</tt>.
+ <br><br>
+
+ <dt><tt>gmake -C runtime install-bytecode</tt>
+ <dd>
+ Assuming you built LLVM into $OBJDIR, when this command is run, it will
+ install bitcode libraries into the GCC front end's bitcode library
+ directory. If you need to update your bitcode libraries,
+ this is the target to use once you've built them.
+ <br><br>
+</dl>
+
+<p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
+details on these <tt>make</tt> targets and descriptions of other targets
+available.</p>
+
+<p>It is also possible to override default values from <tt>configure</tt> by
+declaring variables on the command line. The following are some examples:</p>
+
+<dl>
+ <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
+ <dd>
+ Perform a Release (Optimized) build.
+ <br><br>
+
+ <dt><tt>gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1</tt>
+ <dd>
+ Perform a Release (Optimized) build without assertions enabled.
+ <br><br>
+
+ <dt><tt>gmake ENABLE_OPTIMIZED=0</tt>
+ <dd>
+ Perform a Debug build.
+ <br><br>
+
+ <dt><tt>gmake ENABLE_PROFILING=1</tt>
+ <dd>
+ Perform a Profiling build.
+ <br><br>
+
+ <dt><tt>gmake VERBOSE=1</tt>
+ <dd>
+ Print what <tt>gmake</tt> is doing on standard output.
+ <br><br>
+
+ <dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
+ <dd>Ask each tool invoked by the makefiles to print out what it is doing on
+ the standard output. This also implies <tt>VERBOSE=1</tt>.
+ <br><br></dd>
+</dl>
+
+<p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
+it and any subdirectories that it contains. Entering any directory inside the
+LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
+that directory that is out of date.</p>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="cross-compile">Cross-Compiling LLVM</a>
+</div>
+
+<div class="doc_text">
+ <p>It is possible to cross-compile LLVM itself. That is, you can create LLVM
+ executables and libraries to be hosted on a platform different from the
+ platform where they are build (a Canadian Cross build). To configure a
+ cross-compile, supply the configure script with <tt>--build</tt> and
+ <tt>--host</tt> options that are different. The values of these options must
+ be legal target triples that your GCC compiler supports.</p>
+
+ <p>The result of such a build is executables that are not runnable on
+ on the build host (--build option) but can be executed on the compile host
+ (--host option).</p>
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="objfiles">The Location of LLVM Object Files</a>
+</div>
+
+<div class="doc_text">
+
+<p>The LLVM build system is capable of sharing a single LLVM source tree among
+several LLVM builds. Hence, it is possible to build LLVM for several different
+platforms or configurations using the same source tree.</p>
+
+<p>This is accomplished in the typical autoconf manner:</p>
+
+<ul>
+ <li><p>Change directory to where the LLVM object files should live:</p>
+
+ <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
+
+ <li><p>Run the <tt>configure</tt> script found in the LLVM source
+ directory:</p>
+
+ <div class="doc_code"><pre>% <i>SRC_ROOT</i>/configure</pre></div></li>
+</ul>
+
+<p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
+named after the build type:</p>
+
+<dl>
+ <dt>Debug Builds with assertions enabled (the default)
+ <dd>
+ <dl>
+ <dt>Tools
+ <dd><tt><i>OBJ_ROOT</i>/Debug+Asserts/bin</tt>
+ <dt>Libraries
+ <dd><tt><i>OBJ_ROOT</i>/Debug+Asserts/lib</tt>
+ </dl>
+ <br><br>
+
+ <dt>Release Builds
+ <dd>
+ <dl>
+ <dt>Tools
+ <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
+ <dt>Libraries
+ <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
+ </dl>
+ <br><br>
+
+ <dt>Profile Builds
+ <dd>
+ <dl>
+ <dt>Tools
+ <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
+ <dt>Libraries
+ <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
+ </dl>
+</dl>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="optionalconfig">Optional Configuration Items</a>
+</div>
+
+<div class="doc_text">
+
+<p>
+If you're running on a Linux system that supports the "<a
+href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc</a>"
+module, and you have root access on the system, you can set your system up to
+execute LLVM bitcode files directly. To do this, use commands like this (the
+first command may not be required if you are already using the module):</p>
+
+<div class="doc_code">
+<pre>
+$ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
+$ echo ':llvm:M::BC::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register
+$ chmod u+x hello.bc (if needed)
+$ ./hello.bc
+</pre>
+</div>
+
+<p>
+This allows you to execute LLVM bitcode files directly. On Debian, you
+can also use this command instead of the 'echo' command above:</p>
+</p>
+
+<div class="doc_code">
+<pre>
+$ sudo update-binfmts --install llvm /path/to/lli --magic 'BC'
+</pre>
+</div>
+
+</div>
+
+<!-- *********************************************************************** -->
+<div class="doc_section">
+ <a name="layout"><b>Program Layout</b></a>
+</div>
+<!-- *********************************************************************** -->
+
+<div class="doc_text">
+
+<p>One useful source of information about the LLVM source base is the LLVM <a
+href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
+href="http://llvm.org/doxygen/">http://llvm.org/doxygen/</a></tt>.
+The following is a brief introduction to code layout:</p>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
+<div class="doc_text">
+ <p>This directory contains some simple examples of how to use the LLVM IR and
+ JIT.</p>
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
+<div class="doc_text">
+
+<p>This directory contains public header files exported from the LLVM
+library. The three main subdirectories of this directory are:</p>
+
+<dl>
+ <dt><tt><b>llvm/include/llvm</b></tt></dt>
+ <dd>This directory contains all of the LLVM specific header files. This
+ directory also has subdirectories for different portions of LLVM:
+ <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
+ etc...</dd>
+
+ <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
+ <dd>This directory contains generic support libraries that are provided with
+ LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
+ and a Command Line option processing library store their header files here.
+ </dd>
+
+ <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
+ <dd>This directory contains header files configured by the <tt>configure</tt>
+ script. They wrap "standard" UNIX and C header files. Source code can
+ include these header files which automatically take care of the conditional
+ #includes that the <tt>configure</tt> script generates.</dd>
+</dl>
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
+<div class="doc_text">
+
+<p>This directory contains most of the source files of the LLVM system. In LLVM,
+almost all code exists in libraries, making it very easy to share code among the
+different <a href="#tools">tools</a>.</p>
+
+<dl>
+ <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
+ <dd> This directory holds the core LLVM source files that implement core
+ classes like Instruction and BasicBlock.</dd>
+
+ <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
+ <dd>This directory holds the source code for the LLVM assembly language parser
+ library.</dd>
+
+ <dt><tt><b>llvm/lib/BitCode/</b></tt></dt>
+ <dd>This directory holds code for reading and write LLVM bitcode.</dd>
+
+ <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
+ different program analyses, such as Dominator Information, Call Graphs,
+ Induction Variables, Interval Identification, Natural Loop Identification,
+ etc.</dd>
+
+ <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
+ <dd> This directory contains the source code for the LLVM to LLVM program
+ transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
+ Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
+ Elimination, and many others.</dd>
+
+ <dt><tt><b>llvm/lib/Target/</b></tt></dt>
+ <dd> This directory contains files that describe various target architectures
+ for code generation. For example, the <tt>llvm/lib/Target/X86</tt>
+ directory holds the X86 machine description while
+ <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter.</dd>
+
+ <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
+ <dd> This directory contains the major parts of the code generator: Instruction
+ Selector, Instruction Scheduling, and Register Allocation.</dd>
+
+ <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
+ <dd> This directory contains the source level debugger library that makes
+ it possible to instrument LLVM programs so that a debugger could identify
+ source code locations at which the program is executing.</dd>
+
+ <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
+ <dd> This directory contains libraries for executing LLVM bitcode directly
+ at runtime in both interpreted and JIT compiled fashions.</dd>
+
+ <dt><tt><b>llvm/lib/Support/</b></tt></dt>
+ <dd> This directory contains the source code that corresponds to the header
+ files located in <tt>llvm/include/Support/</tt>.</dd>
+
+ <dt><tt><b>llvm/lib/System/</b></tt></dt>
+ <dd>This directory contains the operating system abstraction layer that
+ shields LLVM from platform-specific coding.</dd>
+</dl>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
+<div class="doc_text">
+ <p>This directory contains projects that are not strictly part of LLVM but are
+ shipped with LLVM. This is also the directory where you should create your own
+ LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
+ to set up your own project.</p>
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
+<div class="doc_text">
+
+<p>This directory contains libraries which are compiled into LLVM bitcode and
+used when linking programs with the GCC front end. Most of these libraries are
+skeleton versions of real libraries; for example, libc is a stripped down
+version of glibc.</p>
+
+<p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
+end to compile.</p>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
+<div class="doc_text">
+ <p>This directory contains feature and regression tests and other basic sanity
+ checks on the LLVM infrastructure. These are intended to run quickly and cover
+ a lot of territory without being exhaustive.</p>
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="test-suite"><tt>test-suite</tt></a></div>
+<div class="doc_text">
+ <p>This is not a directory in the normal llvm module; it is a separate
+ Subversion
+ module that must be checked out (usually to <tt>projects/test-suite</tt>).
+ This
+ module contains a comprehensive correctness, performance, and benchmarking
+ test
+ suite for LLVM. It is a separate Subversion module because not every LLVM
+ user is
+ interested in downloading or building such a comprehensive test suite. For
+ further details on this test suite, please see the
+ <a href="TestingGuide.html">Testing Guide</a> document.</p>
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
+<div class="doc_text">
+
+<p>The <b>tools</b> directory contains the executables built out of the
+libraries above, which form the main part of the user interface. You can
+always get help for a tool by typing <tt>tool_name -help</tt>. The
+following is a brief introduction to the most important tools. More detailed
+information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
+
+<dl>
+
+ <dt><tt><b>bugpoint</b></tt></dt>
+ <dd><tt>bugpoint</tt> is used to debug
+ optimization passes or code generation backends by narrowing down the
+ given test case to the minimum number of passes and/or instructions that
+ still cause a problem, whether it is a crash or miscompilation. See <a
+ href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
+ on using <tt>bugpoint</tt>.</dd>
+
+ <dt><tt><b>llvmc</b></tt></dt>
+ <dd>The LLVM Compiler Driver. This program can
+ be configured to utilize both LLVM and non-LLVM compilation tools to enable
+ pre-processing, translation, optimization, assembly, and linking of programs
+ all from one command line. <tt>llvmc</tt> also takes care of processing the
+ dependent libraries found in bitcode. This reduces the need to get the
+ traditional <tt>-l<name></tt> options right on the command line. Please
+ note that this tool, while functional, is still experimental and not feature
+ complete.</dd>
+
+ <dt><tt><b>llvm-ar</b></tt></dt>
+ <dd>The archiver produces an archive containing
+ the given LLVM bitcode files, optionally with an index for faster
+ lookup.</dd>
+
+ <dt><tt><b>llvm-as</b></tt></dt>
+ <dd>The assembler transforms the human readable LLVM assembly to LLVM
+ bitcode.</dd>
+
+ <dt><tt><b>llvm-dis</b></tt></dt>
+ <dd>The disassembler transforms the LLVM bitcode to human readable
+ LLVM assembly.</dd>
+
+ <dt><tt><b>llvm-ld</b></tt></dt>
+ <dd><tt>llvm-ld</tt> is a general purpose and extensible linker for LLVM.
+ This is the linker invoked by <tt>llvmc</tt>. It performs standard link time
+ optimizations and allows optimization modules to be loaded and run so that
+ language specific optimizations can be applied at link time.</dd>
+
+ <dt><tt><b>llvm-link</b></tt></dt>
+ <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
+ a single program.</dd>
+
+ <dt><tt><b>lli</b></tt></dt>
+ <dd><tt>lli</tt> is the LLVM interpreter, which
+ can directly execute LLVM bitcode (although very slowly...). For architectures
+ that support it (currently x86, Sparc, and PowerPC), by default, <tt>lli</tt>
+ will function as a Just-In-Time compiler (if the functionality was compiled
+ in), and will execute the code <i>much</i> faster than the interpreter.</dd>
+
+ <dt><tt><b>llc</b></tt></dt>
+ <dd> <tt>llc</tt> is the LLVM backend compiler, which
+ translates LLVM bitcode to a native code assembly file or to C code (with
+ the -march=c option).</dd>
+
+ <dt><tt><b>llvm-gcc</b></tt></dt>
+ <dd><tt>llvm-gcc</tt> is a GCC-based C frontend that has been retargeted to
+ use LLVM as its backend instead of GCC's RTL backend. It can also emit LLVM
+ bitcode or assembly (with the <tt>-emit-llvm</tt> option) instead of the
+ usual machine code output. It works just like any other GCC compiler,
+ taking the typical <tt>-c, -S, -E, -o</tt> options that are typically used.
+ Additionally, the the source code for <tt>llvm-gcc</tt> is available as a
+ separate Subversion module.</dd>
+
+ <dt><tt><b>opt</b></tt></dt>
+ <dd><tt>opt</tt> reads LLVM bitcode, applies a series of LLVM to LLVM
+ transformations (which are specified on the command line), and then outputs
+ the resultant bitcode. The '<tt>opt -help</tt>' command is a good way to
+ get a list of the program transformations available in LLVM.<br>
+ <dd><tt>opt</tt> can also be used to run a specific analysis on an input
+ LLVM bitcode file and print out the results. It is primarily useful for
+ debugging analyses, or familiarizing yourself with what an analysis does.</dd>
+</dl>
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
+<div class="doc_text">
+
+<p>This directory contains utilities for working with LLVM source code, and some
+of the utilities are actually required as part of the build process because they
+are code generators for parts of LLVM infrastructure.</p>
+
+<dl>
+ <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
+ that finds differences between code that LLC generates and code that LLI
+ generates. This is a useful tool if you are debugging one of them,
+ assuming that the other generates correct output. For the full user
+ manual, run <tt>`perldoc codegen-diff'</tt>.<br><br>
+
+ <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
+ syntax-highlighting files which will work with Emacs and XEmacs editors,
+ providing syntax highlighting support for LLVM assembly files and TableGen
+ description files. For information on how to use the syntax files, consult
+ the <tt>README</tt> file in that directory.<br><br>
+
+ <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
+ and outputs all non-generated source files, which is useful if one wishes
+ to do a lot of development across directories and does not want to
+ individually find each file. One way to use it is to run, for example:
+ <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
+ tree.<br><br>
+
+ <dt><tt><b>llvmgrep</b></tt></dt>
+ <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
+ passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
+ line. This is a very efficient way of searching the source base for a
+ particular regular expression.</dd>
+
+ <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
+ files in the current directory and then compiles and links the tool that
+ is the first argument. For example, assuming you are in the directory
+ <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
+ simply running <tt>makellvm llc</tt> will make a build of the current
+ directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
+ causing a re-linking of LLC.<br><br>
+
+ <dt><tt><b>NewNightlyTest.pl</b></tt> and
+ <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
+ cron script to generate nightly status reports of the functionality of
+ tools, and the results can be seen by following the appropriate link on
+ the <a href="http://llvm.org/">LLVM homepage</a>.<br><br>
+
+ <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
+ the tool used to generate register descriptions, instruction set
+ descriptions, and even assemblers from common TableGen description
+ files.<br><br>
+
+ <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
+ syntax-highlighting files which will work with the VIM editor, providing
+ syntax highlighting support for LLVM assembly files and TableGen
+ description files. For information on how to use the syntax files, consult
+ the <tt>README</tt> file in that directory.<br><br>
+
+</dl>
+
+</div>
+
+<!-- *********************************************************************** -->
+<div class="doc_section">
+ <a name="tutorial">An Example Using the LLVM Tool Chain</a>
+</div>
+<!-- *********************************************************************** -->
+
+<div class="doc_text">
+<p>This section gives an example of using LLVM. llvm-gcc3 is now obsolete,
+so we only include instructions for llvm-gcc4.
+</p>
+
+<p><b>Note:</b> The <i>gcc4</i> frontend's invocation is <b><i>considerably different</i></b>
+from the previous <i>gcc3</i> frontend. In particular, the <i>gcc4</i> frontend <b><i>does not</i></b>
+create bitcode by default: <i>gcc4</i> produces native code. As the example below illustrates,
+the '--emit-llvm' flag is needed to produce LLVM bitcode output. For <i>makefiles</i> and
+<i>configure</i> scripts, the CFLAGS variable needs '--emit-llvm' to produce bitcode
+output.</p>
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="tutorial4">Example with llvm-gcc4</a></div>
+
+<div class="doc_text">
+
+<ol>
+ <li><p>First, create a simple C file, name it 'hello.c':</p>
+
+<div class="doc_code">
+<pre>
+#include <stdio.h>
+
+int main() {
+ printf("hello world\n");
+ return 0;
+}
+</pre></div></li>
+
+ <li><p>Next, compile the C file into a native executable:</p>
+
+ <div class="doc_code"><pre>% llvm-gcc hello.c -o hello</pre></div>
+
+ <p>Note that llvm-gcc works just like GCC by default. The standard -S and
+ -c arguments work as usual (producing a native .s or .o file,
+ respectively).</p></li>
+
+ <li><p>Next, compile the C file into a LLVM bitcode file:</p>
+
+ <div class="doc_code">
+ <pre>% llvm-gcc -O3 -emit-llvm hello.c -c -o hello.bc</pre></div>
+
+ <p>The -emit-llvm option can be used with the -S or -c options to emit an
+ LLVM ".ll" or ".bc" file (respectively) for the code. This allows you
+ to use the <a href="CommandGuide/index.html">standard LLVM tools</a> on
+ the bitcode file.</p>
+
+ <p>Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments.
+ </p></li>
+
+ <li><p>Run the program in both forms. To run the program, use:</p>
+
+ <div class="doc_code"><pre>% ./hello</pre></div>
+
+ <p>and</p>
- <p>
- If you have multiple processors in your machine, you may wish to use some
- of the parallel build options provided by GNU Make. For example, you could
- use the command:
- </p>
+ <div class="doc_code"><pre>% lli hello.bc</pre></div>
- <p>
- <tt>gmake -j2</tt>
+ <p>The second examples shows how to invoke the LLVM JIT, <a
+ href="CommandGuide/html/lli.html">lli</a>.</p></li>
- <p>
- There are several other targets which are useful when working with the LLVM
- source code:
-
- <dl compact>
- <dt><tt>gmake clean</tt>
- <dd>
- Removes all files generated by the build. This includes object files,
- generated C/C++ files, libraries, and executables.
- <p>
-
- <dt><tt>gmake distclean</tt>
- <dd>
- Removes everything that <tt>gmake clean</tt> does, but also removes
- files generated by <tt>configure</tt>. It attempts to return the
- source tree to the original state in which it was shipped.
- <p>
- </dl>
-
- It is also possible to override default values from <tt>configure</tt> by
- declaring variables on the command line. The following are some examples:
-
- <dl compact>
- <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
- <dd>
- Perform a Release (Optimized) build.
- <p>
-
- <dt><tt>gmake ENABLE_PROFILING=1</tt>
- <dd>
- Perform a Profiling build.
- <p>
-
- <dt><tt>gmake VERBOSE=1</tt>
- <dd>
- Print what <tt>gmake</tt> is doing on standard output.
- <p>
- </dl>
-
- Every directory in the LLVM source tree includes a <tt>Makefile</tt> to
- build it and any subdirectories that it contains. Entering any directory
- inside the LLVM source tree and typing <tt>gmake</tt> should rebuild
- anything in or below that directory that is out of date.
-
- <!------------------------------------------------------------------------->
- <h3><a name="objfiles">The Location of LLVM Object Files</a></h3>
- <!------------------------------------------------------------------------->
-
- <p>The LLVM build system sends most output files generated during the build
- into the directory defined by the variable <i>OBJ_ROOT</i> in
- <tt>llvm/Makefile.config</tt>, which is set by the <i>--with-objroot</i>
- option in <tt>configure</tt>. This can be either just your normal LLVM
- source tree or some other directory writable by you. You may wish to put
- object files on a different filesystem either to keep them from being backed
- up or to speed up local builds.
+ <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
+ code:</p>
- <p>
- If <i>OBJ_ROOT</i> is specified, then the build system will create a
- directory tree underneath it that resembles the source code's pathname
- relative to your home directory (unless <i>OBJ_ROOT</i> is set to
- <tt>.</tt>, in which case object files are placed within the LLVM source
- tree).
- </p>
+<div class="doc_code">
+<pre>llvm-dis < hello.bc | less</pre>
+</div></li>
- <p>
- Note that
- <i>--with-objroot</i>=<tt>.</tt>
- and
- <i>--with-objroot</i>=<tt>`pwd`</tt>
- are not the same thing. The former will simply place object files within
- the source tree, while the latter will set the location of object files
- using the source tree's relative path from the home directory.
- </p>
+ <li><p>Compile the program to native assembly using the LLC code
+ generator:</p>
- <p>
- For example, suppose that <i>OBJ_ROOT</i> is set to <tt>/tmp</tt> and the
- LLVM suite source code is located in <tt>/usr/home/joe/src/llvm</tt>, where
- <tt>/usr/home/joe</tt> is the home directory of a user named Joe. Then,
- the object files will be placed in <tt>/tmp/src/llvm</tt>.
- </p>
+ <div class="doc_code"><pre>% llc hello.bc -o hello.s</pre></div></li>
- <p>
- The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
- named after the build type:
- </p>
-
- <dl compact>
- <dt>Debug Builds
- <dd>
- <dl compact>
- <dt>Tools
- <dd><tt><i>OBJ_ROOT</i>/llvm/tools/Debug</tt>
- <dt>Libraries
- <dd><tt><i>OBJ_ROOT</i>/llvm/lib/Debug</tt>
- </dl>
- <p>
-
- <dt>Release Builds
- <dd>
- <dl compact>
- <dt>Tools
- <dd><tt><i>OBJ_ROOT</i>/llvm/tools/Release</tt>
- <dt>Libraries
- <dd><tt><i>OBJ_ROOT</i>/llvm/lib/Release</tt>
- </dl>
- <p>
-
- <dt>Profile Builds
- <dd>
- <dl compact>
- <dt>Tools
- <dd><tt><i>OBJ_ROOT</i>/llvm/tools/Profile</tt>
- <dt>Libraries
- <dd><tt><i>OBJ_ROOT</i>/llvm/lib/Profile</tt>
- </dl>
- </dl>
-
- <!--=====================================================================-->
- <center>
- <h2><a name="layout"><b>Program Layout</b></a></h2>
- </center>
- <!--=====================================================================-->
-
- <p>One useful source of information about the LLVM source base is the LLVM <a
- href="http://www.doxygen.org">doxygen</a> documentation, available at <tt><a
- href="http://llvm.cs.uiuc.edu/doxygen/">http://llvm.cs.uiuc.edu/doxygen/</a></tt>. The
- following is a brief introduction to code layout:</p>
-
-
- <!------------------------------------------------------------------------->
- <h3><a name="cvsdir"><tt>CVS</tt> directories</a></h3>
- <!------------------------------------------------------------------------->
-
- Every directory checked out of CVS will contain a <tt>CVS</tt> directory;
- for the most part these can just be ignored.
-
-
- <!------------------------------------------------------------------------->
- <h3><a name="include"><tt>llvm/include</tt></a></h3>
- <!------------------------------------------------------------------------->
-
- This directory contains public header files exported from the LLVM
- library. The three main subdirectories of this directory are:<p>
+ <li><p>Assemble the native assembly language file into a program:</p>
- <ol>
- <li><tt>llvm/include/llvm</tt> - This directory contains all of the LLVM
- specific header files. This directory also has subdirectories for
- different portions of LLVM: <tt>Analysis</tt>, <tt>CodeGen</tt>,
- <tt>Reoptimizer</tt>, <tt>Target</tt>, <tt>Transforms</tt>, etc...
-
- <li><tt>llvm/include/Support</tt> - This directory contains generic
- support libraries that are independent of LLVM, but are used by LLVM.
- For example, some C++ STL utilities and a Command Line option processing
- library.
-
- <li><tt>llvm/include/Config</tt> - This directory contains header files
- configured by the <tt>configure</tt> script. They wrap "standard" UNIX
- and C header files. Source code can include these header files which
- automatically take care of the conditional #includes that the configure
- script generates.
- </ol>
-
- <!------------------------------------------------------------------------->
- <h3><a name="lib"><tt>llvm/lib</tt></a></h3>
- <!------------------------------------------------------------------------->
-
- This directory contains most of the source files of the LLVM system. In
- LLVM almost all
- code exists in libraries, making it very easy to share code among the
- different <a href="#tools">tools</a>.<p>
-
- <dl compact>
- <dt><tt>llvm/lib/VMCore/</tt><dd> This directory holds the core LLVM
- source files that implement core classes like Instruction and BasicBlock.
-
- <dt><tt>llvm/lib/AsmParser/</tt><dd> This directory holds the source code
- for the LLVM assembly language parser library.
-
- <dt><tt>llvm/lib/ByteCode/</tt><dd> This directory holds code for reading
- and write LLVM bytecode.
-
- <dt><tt>llvm/lib/CWriter/</tt><dd> This directory implements the LLVM to C
- converter.
-
- <dt><tt>llvm/lib/Analysis/</tt><dd> This directory contains a variety of
- different program analyses, such as Dominator Information, Call Graphs,
- Induction Variables, Interval Identification, Natural Loop Identification,
- etc...
-
- <dt><tt>llvm/lib/Transforms/</tt><dd> This directory contains the source
- code for the LLVM to LLVM program transformations, such as Aggressive Dead
- Code Elimination, Sparse Conditional Constant Propagation, Inlining, Loop
- Invarient Code Motion, Dead Global Elimination, and many others...
-
- <dt><tt>llvm/lib/Target/</tt><dd> This directory contains files that
- describe various target architectures for code generation. For example,
- the llvm/lib/Target/Sparc directory holds the Sparc machine
- description.<br>
-
- <dt><tt>llvm/lib/CodeGen/</tt><dd> This directory contains the major parts
- of the code generator: Instruction Selector, Instruction Scheduling, and
- Register Allocation.
-
- <dt><tt>llvm/lib/Reoptimizer/</tt><dd> This directory holds code related
- to the runtime reoptimizer framework that is currently under development.
-
- <dt><tt>llvm/lib/Support/</tt><dd> This directory contains the source code
- that corresponds to the header files located in
- <tt>llvm/include/Support/</tt>.
- </dl>
-
- <!------------------------------------------------------------------------->
- <h3><a name="test"><tt>llvm/test</tt></a></h3>
- <!------------------------------------------------------------------------->
-
- <p>This directory contains regression tests and source code that is used to
- test the LLVM infrastructure...</p>
-
- <!------------------------------------------------------------------------->
- <h3><a name="tools"><tt>llvm/tools</tt></a></h3>
- <!------------------------------------------------------------------------->
-
- <p>The <b>tools</b> directory contains the executables built out of the
- libraries above, which form the main part of the user interface. You can
- always get help for a tool by typing <tt>tool_name --help</tt>. The
- following is a brief introduction to the most important tools.</p>
-
- <dl compact>
- <dt><tt><b>llvm-as</b></tt><dd>The assembler transforms the human readable
- LLVM assembly to LLVM bytecode.<p>
-
- <dt><tt><b>llvm-dis</b></tt><dd>The disassembler transforms the LLVM
- bytecode to human readable LLVM assembly. Additionally it can convert
- LLVM bytecode to C, which is enabled with the <tt>-c</tt> option.<p>
-
- <dt><tt><b>lli</b></tt><dd> <tt>lli</tt> is the LLVM interpreter, which
- can directly execute LLVM bytecode (although very slowly...). In addition
- to a simple interpreter, <tt>lli</tt> is also has debugger and tracing
- modes (entered by specifying <tt>-debug</tt> or <tt>-trace</tt> on the
- command line, respectively). Finally, for architectures that support it
- (currently only x86 and Sparc), by default, <tt>lli</tt> will function as
- a Just-In-Time compiler (if the functionality was compiled in), and will
- execute the code <i>much</i> faster than the interpreter.<p>
-
- <dt><tt><b>llc</b></tt><dd> <tt>llc</tt> is the LLVM backend compiler,
- which translates LLVM bytecode to a SPARC or x86 assembly file.<p>
-
- <dt><tt><b>llvmgcc</b></tt><dd> <tt>llvmgcc</tt> is a GCC based C frontend
- that has been retargeted to emit LLVM code as the machine code output. It
- works just like any other GCC compiler, taking the typical <tt>-c, -S, -E,
- -o</tt> options that are typically used. The source code for the
- <tt>llvmgcc</tt> tool is currently not included in the LLVM cvs tree
- because it is quite large and not very interesting.<p>
+<div class="doc_code">
+<pre>
+<b>Solaris:</b> % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native
- <ol>
- <dt><tt><b>gccas</b></tt><dd> This tool is invoked by the
- <tt>llvmgcc</tt> frontend as the "assembler" part of the compiler. This
- tool actually assembles LLVM assembly to LLVM bytecode,
- performs a variety of optimizations,
- and outputs LLVM bytecode. Thus when you invoke <tt>llvmgcc -c x.c -o
- x.o</tt>, you are causing <tt>gccas</tt> to be run, which writes the
- <tt>x.o</tt> file (which is an LLVM bytecode file that can be
- disassembled or manipulated just like any other bytecode file). The
- command line interface to <tt>gccas</tt> is designed to be as close as
- possible to the <b>system</b> `<tt>as</tt>' utility so that the gcc
- frontend itself did not have to be modified to interface to a "weird"
- assembler.<p>
-
- <dt><tt><b>gccld</b></tt><dd> <tt>gccld</tt> links together several LLVM
- bytecode files into one bytecode file and does some optimization. It is
- the linker invoked by the gcc frontend when multiple .o files need to be
- linked together. Like <tt>gccas</tt> the command line interface of
- <tt>gccld</tt> is designed to match the system linker, to aid
- interfacing with the GCC frontend.<p>
- </ol>
+<b>Others:</b> % gcc hello.s -o hello.native
+</pre>
+</div></li>
- <dt><tt><b>opt</b></tt><dd> <tt>opt</tt> reads LLVM bytecode, applies a
- series of LLVM to LLVM transformations (which are specified on the command
- line), and then outputs the resultant bytecode. The '<tt>opt --help</tt>'
- command is a good way to get a list of the program transformations
- available in LLVM.<p>
+ <li><p>Execute the native code program:</p>
-
- <dt><tt><b>analyze</b></tt><dd> <tt>analyze</tt> is used to run a specific
- analysis on an input LLVM bytecode file and print out the results. It is
- primarily useful for debugging analyses, or familiarizing yourself with
- what an analysis does.<p>
-
- </dl>
-
- <!------------------------------------------------------------------------->
- <h3><a name="utils"><tt>llvm/utils</tt></a></h3>
- <!------------------------------------------------------------------------->
-
- This directory contains utilities for working with LLVM sourcecode, and some
- of the utilities are actually required as part of the build process because
- they are code generators for parts of LLVM infrastructure.
-
- <dl compact>
- <td><tt><b>Burg/</b></tt><dd> <tt>Burg</tt> is an instruction selector
- generator -- it builds trees on which it then performs pattern-matching to
- select instructions according to the patterns the user has specified. Burg
- is currently used in the Sparc V9 backend.<p>
-
- <dt><tt><b>codegen-diff</b></tt><dd> <tt>codegen-diff</tt> is a script
- that finds differences between code that LLC generates and code that LLI
- generates. This is a useful tool if you are debugging one of them,
- assuming that the other generates correct output. For the full user
- manual, run <tt>`perldoc codegen-diff'</tt>.<p>
-
- <dt><tt><b>cvsupdate</b></tt><dd> <tt>cvsupdate</tt> is a script that will
- update your CVS tree, but produce a much cleaner and more organized output
- than simply running <tt>`cvs up -dP'</tt> will. For example, it will group
- together all the new and updated files and modified files in separate
- sections, so you can see at a glance what has changed. If you are at the
- top of your LLVM CVS tree, running <tt>utils/cvsupdate</tt> is the
- preferred way of updating the tree.<p>
-
- <dt><tt><b>emacs/</b></tt><dd> The <tt>emacs</tt> directory contains
- syntax-highlighting files which will work with Emacs and XEmacs editors,
- providing syntax highlighting support for LLVM assembly files and TableGen
- description files. For information on how to use the syntax files, consult
- the <tt>README</tt> file in that directory.<p>
-
- <dt><tt><b>getsrcs.sh</b></tt><dd> The <tt>getsrcs.sh</tt> script finds
- and outputs all non-generated source files, which is useful if one wishes
- to do a lot of development across directories and does not want to
- individually find each file. One way to use it is to run, for example:
- <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
- tree.<p>
-
- <dt><tt><b>makellvm</b></tt><dd> The <tt>makellvm</tt> script compiles all
- files in the current directory and then compiles and links the tool that
- is the first argument. For example, assuming you are in the directory
- <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
- simply running <tt>makellvm llc</tt> will make a build of the current
- directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
- causing a re-linking of LLC.<p>
-
- <dt><tt><b>NightlyTest.pl</b></tt> and
- <tt><b>NightlyTestTemplate.html</b></tt><dd> These files are used in a
- cron script to generate nightly status reports of the functionality of
- tools, and the results can be seen by following the appropriate link on
- the <a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a>.<p>
-
- <dt><tt><b>TableGen/</b></tt><dd> The <tt>TableGen</tt> directory contains
- the tool used to generate register descriptions, instruction set
- descriptions, and even assemblers from common TableGen description
- files.<p>
-
- <dt><tt><b>vim/</b></tt><dd> The <tt>vim</tt> directory contains
- syntax-highlighting files which will work with the VIM editor, providing
- syntax highlighting support for LLVM assembly files and TableGen
- description files. For information on how to use the syntax files, consult
- the <tt>README</tt> file in that directory.<p>
-
- </dl>
+ <div class="doc_code"><pre>% ./hello.native</pre></div>
- <!--=====================================================================-->
- <h2><center><a name="cfront">Compiling the LLVM C Front End</center></h2>
- <!--=====================================================================-->
+ <p>Note that using llvm-gcc to compile directly to native code (i.e. when
+ the -emit-llvm option is not present) does steps 6/7/8 for you.</p>
+ </li>
- <p>
- <b>
- This step is optional if you have the C front end binary distribution for
- your platform.
- </b>
- </p>
-
- Now that you have the LLVM suite built, you can build the C front end. For
- those of you that have built GCC before, the process is very similar.
- <p>
- Be forewarned, though: the build system for the C front end is not as
- polished as the rest of the LLVM code, so there will be many warnings and
- errors that you will need to ignore for now:
+</ol>
- <ol>
- <li>Ensure that <tt><i>OBJ_ROOT</i>/llvm/tools/Debug</tt> is at the
- <i>end</i> of your <tt>PATH</tt> environment variable. The front end
- build needs to know where to find the LLVM tools, but you want to
- ensure that these tools are not found before the system assembler and
- linker that you normally use for compilation.
+</div>
- <li><tt>cd <i>GCCOBJ</i></tt>
- <li>Configure the source code:
- <ul>
- <li>On Linux/x86, use
- <ul>
- <li><tt><i>GCCSRC</i>/configure --prefix=<i>LLVMGCCDIR</i>
- --enable-languages=c</tt>
- </ul>
+<!-- *********************************************************************** -->
+<div class="doc_section">
+ <a name="problems">Common Problems</a>
+</div>
+<!-- *********************************************************************** -->
- <li>On Solaris/Sparc, use
- <ul>
- <li><tt><i>GCCSRC</i>/configure --prefix=<i>LLVMGCCDIR</i>
- --enable-languages=c --target=sparcv9-sun-solaris2</tt>
- </ul>
- </ul>
+<div class="doc_text">
- <li><tt>gmake</tt>
+<p>If you are having problems building or using LLVM, or if you have any other
+general questions about LLVM, please consult the <a href="FAQ.html">Frequently
+Asked Questions</a> page.</p>
- <li>The build will eventually fail. Don't worry; chances are good that
- everything that needed to build is built.
+</div>
- <li><tt>gmake -k install</tt>
- </ol>
+<!-- *********************************************************************** -->
+<div class="doc_section">
+ <a name="links">Links</a>
+</div>
+<!-- *********************************************************************** -->
- <p>
- Once this is done, you should have a built front end compiler in
- <tt><i>LLVMGCCDIR</i></tt>.
- </p>
+<div class="doc_text">
- <!--=====================================================================-->
- <h2>
- <center><a name="tutorial">An Example Using the LLVM Tool Chain</center>
- </h2>
- <!--=====================================================================-->
+<p>This document is just an <b>introduction</b> on how to use LLVM to do
+some simple things... there are many more interesting and complicated things
+that you can do that aren't documented here (but we'll gladly accept a patch
+if you want to write something up!). For more information about LLVM, check
+out:</p>
- <ol>
- <li>First, create a simple C file, name it 'hello.c':
- <pre>
- #include <stdio.h>
- int main() {
- printf("hello world\n");
- return 0;
- }
- </pre>
-
- <li>Next, compile the C file into a LLVM bytecode file:<p>
-
- <tt>% llvmgcc hello.c -o hello</tt><p>
-
- This will create two result files: <tt>hello</tt> and
- <tt>hello.bc</tt>. The <tt>hello.bc</tt> is the LLVM bytecode that
- corresponds the the compiled program and the library facilities that it
- required. <tt>hello</tt> is a simple shell script that runs the bytecode
- file with <tt>lli</tt>, making the result directly executable.<p>
-
- <li>Run the program. To make sure the program ran, execute one of the
- following commands:<p>
-
- <tt>% ./hello</tt><p>
-
- or<p>
-
- <tt>% lli hello.bc</tt><p>
-
- <li>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
- code:<p>
-
- <tt>% llvm-dis < hello.bc | less</tt><p>
-
- <li>Compile the program to native Sparc assembly using the code
- generator (assuming you are currently on a Sparc system):<p>
-
- <tt>% llc hello.bc -o hello.s</tt><p>
-
- <li>Assemble the native sparc assemble file into a program:<p>
-
- <tt>% /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.sparc</tt><p>
-
- <li>Execute the native sparc program:<p>
-
- <tt>% ./hello.sparc</tt><p>
-
- </ol>
-
-
- <!--=====================================================================-->
- <h2>
- <center><a name="problems">Common Problems</a></center>
- </h2>
- <!--=====================================================================-->
-
- Below are common problems and their remedies:
-
- <dl compact>
- <dt><b>When I run configure, it finds the wrong C compiler.</b>
- <dd>
- The <tt>configure</tt> script attempts to locate first <tt>gcc</tt> and
- then <tt>cc</tt>, unless it finds compiler paths set in <tt>CC</tt> and
- <tt>CXX</tt> for the C and C++ compiler, respectively.
-
- If <tt>configure</tt> finds the wrong compiler, either adjust your
- <tt>PATH</tt> environment variable or set <tt>CC</tt> and <tt>CXX</tt>
- explicitly.
- <p>
-
- <dt><b>I compile the code, and I get some error about /localhome</b>.
- <dd>
- There are several possible causes for this. The first is that you
- didn't set a pathname properly when using <tt>configure</tt>, and it
- defaulted to a pathname that we use on our research machines.
- <p>
- Another possibility is that we hardcoded a path in our Makefiles. If
- you see this, please email the LLVM bug mailing list with the name of
- the offending Makefile and a description of what is wrong with it.
-
- <dt><b>The <tt>configure</tt> script finds the right C compiler, but it
- uses the LLVM linker from a previous build. What do I do?</b>
- <dd>
- The <tt>configure</tt> script uses the <tt>PATH</tt> to find
- executables, so if it's grabbing the wrong linker/assembler/etc, there
- are two ways to fix it:
- <ol>
- <li>Adjust your <tt>PATH</tt> environment variable so that the
- correct program appears first in the <tt>PATH</tt>. This may work,
- but may not be convenient when you want them <i>first</i> in your
- path for other work.
- <p>
-
- <li>Run <tt>configure</tt> with an alternative <tt>PATH</tt> that
- is correct. In a Borne compatible shell, the syntax would be:
- <p>
- <tt>PATH=<the path without the bad program> ./configure ...</tt>
- <p>
- This is still somewhat inconvenient, but it allows
- <tt>configure</tt> to do its work without having to adjust your
- <tt>PATH</tt> permanently.
- </ol>
-
- <dt><b>I've upgraded to a new version of LLVM, and I get strange build
- errors.</b>
- <dd>
- Sometimes changes to the LLVM source code alters how the build system
- works. Changes in libtool, autoconf, or header file dependencies are
- especially prone to this sort of problem.
- <p>
- The best thing to try is to remove the old files and re-build. In most
- cases, this takes care of the problem. To do this, just type <tt>make
- clean</tt> and then <tt>make</tt> in the directory that fails to build.
- <p>
-
- </dl>
-
- <!--=====================================================================-->
- <h2><center><a name="links">Links</a></center></h2>
- <!--=====================================================================-->
-
- <p>This document is just an <b>introduction</b> to how to use LLVM to do
- some simple things... there are many more interesting and complicated things
- that you can do that aren't documented here (but we'll gladly accept a patch
- if you want to write something up!). For more information about LLVM, check
- out:</p>
-
- <ul>
- <li><a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/doxygen/">LLVM doxygen tree</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/docs/Projects.html">Starting a Project that Uses LLVM</a></li>
- </ul>
-
- <hr>
-
- If you have any questions or run into any snags (or you have any
- additions...), please send an email to
- <a href="mailto:sabre@nondot.org">Chris Lattner</a>.</p>
-
- <!-- Created: Mon Jul 1 02:29:02 CDT 2002 -->
- <!-- hhmts start -->
-Last modified: Mon Aug 11 13:52:22 CDT 2003
-<!-- hhmts end -->
- </body>
+<ul>
+ <li><a href="http://llvm.org/">LLVM homepage</a></li>
+ <li><a href="http://llvm.org/doxygen/">LLVM doxygen tree</a></li>
+ <li><a href="http://llvm.org/docs/Projects.html">Starting a Project
+ that Uses LLVM</a></li>
+</ul>
+
+</div>
+
+<!-- *********************************************************************** -->
+
+<hr>
+<address>
+ <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
+ src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
+ <a href="http://validator.w3.org/check/referer"><img
+ src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
+
+ <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
+ <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
+ <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
+ Last modified: $Date$
+</address>
+</body>
</html>
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